Hi Doug,
this looks generally good to me, but I don't think open_cnt and exclude
have to use atomic_t, as they are only ever modified under open_rel_lock.
Can you take a look at the version below? This changes open_cnt to an
int, exclude to a bool, removes the open_cnt underflow check that
the VFS takes care for, and streamlines the open path a little bit:
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index e75f71e..0cd77a3 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -51,6 +51,7 @@ static int sg_version_num = 30534; /* 2 digits for each
component */
#include <linux/delay.h>
#include <linux/blktrace_api.h>
#include <linux/mutex.h>
+#include <linux/atomic.h>
#include <linux/ratelimit.h>
#include "scsi.h"
@@ -102,18 +103,16 @@ static int scatter_elem_sz_prev = SG_SCATTER_SZ;
#define SG_SECTOR_SZ 512
-static int sg_add(struct device *, struct class_interface *);
-static void sg_remove(struct device *, struct class_interface *);
-
-static DEFINE_SPINLOCK(sg_open_exclusive_lock);
+static int sg_add_device(struct device *, struct class_interface *);
+static void sg_remove_device(struct device *, struct class_interface *);
static DEFINE_IDR(sg_index_idr);
static DEFINE_RWLOCK(sg_index_lock); /* Also used to lock
file descriptor list
for device */
static struct class_interface sg_interface = {
- .add_dev = sg_add,
- .remove_dev = sg_remove,
+ .add_dev = sg_add_device,
+ .remove_dev = sg_remove_device,
};
typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info
*/
@@ -146,8 +145,7 @@ typedef struct sg_request { /* SG_MAX_QUEUE requests
outstanding per file */
} Sg_request;
typedef struct sg_fd { /* holds the state of a file descriptor */
- /* sfd_siblings is protected by sg_index_lock */
- struct list_head sfd_siblings;
+ struct list_head sfd_siblings; /* protected by device's sfd_lock */
struct sg_device *parentdp; /* owning device */
wait_queue_head_t read_wait; /* queue read until command done */
rwlock_t rq_list_lock; /* protect access to list in req_arr */
@@ -170,14 +168,15 @@ typedef struct sg_fd { /* holds the state of a
file descriptor */
typedef struct sg_device { /* holds the state of each scsi generic device */
struct scsi_device *device;
- wait_queue_head_t o_excl_wait; /* queue open() when O_EXCL in use */
+ wait_queue_head_t open_wait; /* queue open() when O_EXCL present */
+ struct mutex open_rel_lock; /* held when in open() or release() */
int sg_tablesize; /* adapter's max scatter-gather table size */
u32 index; /* device index number */
- /* sfds is protected by sg_index_lock */
struct list_head sfds;
- volatile char detached; /* 0->attached, 1->detached pending removal */
- /* exclude protected by sg_open_exclusive_lock */
- char exclude; /* opened for exclusive access */
+ rwlock_t sfd_lock; /* protect access to sfd list */
+ atomic_t detaching; /* 0->device usable, 1->device detaching */
+ bool exclude; /* 1->open(O_EXCL) succeeded and is active */
+ int open_cnt; /* count of opens (perhaps < num(sfds) ) */
char sgdebug; /* 0->off, 1->sense, 9->dump dev, 10-> all devs
*/
struct gendisk *disk;
struct cdev * cdev; /* char_dev [sysfs: /sys/cdev/major/sg<n>] */
@@ -208,7 +207,7 @@ static Sg_request *sg_add_request(Sg_fd * sfp);
static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
static int sg_res_in_use(Sg_fd * sfp);
static Sg_device *sg_get_dev(int dev);
-static void sg_put_dev(Sg_device *sdp);
+static void sg_device_destroy(struct kref *kref);
#define SZ_SG_HEADER sizeof(struct sg_header)
#define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
@@ -225,38 +224,43 @@ static int sg_allow_access(struct file *filp, unsigned
char *cmd)
return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
}
-static int get_exclude(Sg_device *sdp)
-{
- unsigned long flags;
- int ret;
-
- spin_lock_irqsave(&sg_open_exclusive_lock, flags);
- ret = sdp->exclude;
- spin_unlock_irqrestore(&sg_open_exclusive_lock, flags);
- return ret;
-}
-
-static int set_exclude(Sg_device *sdp, char val)
+static int
+open_wait(Sg_device *sdp, int flags)
{
- unsigned long flags;
-
- spin_lock_irqsave(&sg_open_exclusive_lock, flags);
- sdp->exclude = val;
- spin_unlock_irqrestore(&sg_open_exclusive_lock, flags);
- return val;
-}
+ int retval = 0;
-static int sfds_list_empty(Sg_device *sdp)
-{
- unsigned long flags;
- int ret;
+ if (flags & O_EXCL) {
+ while (sdp->open_cnt > 0) {
+ mutex_unlock(&sdp->open_rel_lock);
+ retval = wait_event_interruptible(sdp->open_wait,
+ (atomic_read(&sdp->detaching) ||
+ !sdp->open_cnt));
+ mutex_lock(&sdp->open_rel_lock);
+
+ if (retval) /* -ERESTARTSYS */
+ return retval;
+ if (atomic_read(&sdp->detaching))
+ return -ENODEV;
+ }
+ } else {
+ while (sdp->exclude) {
+ mutex_unlock(&sdp->open_rel_lock);
+ retval = wait_event_interruptible(sdp->open_wait,
+ (atomic_read(&sdp->detaching) ||
+ !sdp->exclude));
+ mutex_lock(&sdp->open_rel_lock);
+
+ if (retval) /* -ERESTARTSYS */
+ return retval;
+ if (atomic_read(&sdp->detaching))
+ return -ENODEV;
+ }
+ }
- read_lock_irqsave(&sg_index_lock, flags);
- ret = list_empty(&sdp->sfds);
- read_unlock_irqrestore(&sg_index_lock, flags);
- return ret;
+ return retval;
}
+/* Returns 0 on success, else a negated errno value */
static int
sg_open(struct inode *inode, struct file *filp)
{
@@ -265,17 +269,15 @@ sg_open(struct inode *inode, struct file *filp)
struct request_queue *q;
Sg_device *sdp;
Sg_fd *sfp;
- int res;
int retval;
nonseekable_open(inode, filp);
SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev,
flags));
+ if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
+ return -EPERM; /* Can't lock it with read only access */
sdp = sg_get_dev(dev);
- if (IS_ERR(sdp)) {
- retval = PTR_ERR(sdp);
- sdp = NULL;
- goto sg_put;
- }
+ if (IS_ERR(sdp))
+ return PTR_ERR(sdp);
/* This driver's module count bumped by fops_get in <linux/fs.h> */
/* Prevent the device driver from vanishing while we sleep */
@@ -287,6 +289,9 @@ sg_open(struct inode *inode, struct file *filp)
if (retval)
goto sdp_put;
+ /* scsi_block_when_processing_errors() may block so bypass
+ * check if O_NONBLOCK. Permits SCSI commands to be issued
+ * during error recovery. Tread carefully. */
if (!((flags & O_NONBLOCK) ||
scsi_block_when_processing_errors(sdp->device))) {
retval = -ENXIO;
@@ -294,65 +299,65 @@ sg_open(struct inode *inode, struct file *filp)
goto error_out;
}
- if (flags & O_EXCL) {
- if (O_RDONLY == (flags & O_ACCMODE)) {
- retval = -EPERM; /* Can't lock it with read only access
*/
- goto error_out;
- }
- if (!sfds_list_empty(sdp) && (flags & O_NONBLOCK)) {
- retval = -EBUSY;
- goto error_out;
- }
- res = wait_event_interruptible(sdp->o_excl_wait,
- ((!sfds_list_empty(sdp) ||
get_exclude(sdp)) ? 0 : set_exclude(sdp, 1)));
- if (res) {
- retval = res; /* -ERESTARTSYS because signal hit
process */
- goto error_out;
- }
- } else if (get_exclude(sdp)) { /* some other fd has an exclusive lock
on dev */
- if (flags & O_NONBLOCK) {
- retval = -EBUSY;
- goto error_out;
- }
- res = wait_event_interruptible(sdp->o_excl_wait,
!get_exclude(sdp));
- if (res) {
- retval = res; /* -ERESTARTSYS because signal hit
process */
- goto error_out;
+ mutex_lock(&sdp->open_rel_lock);
+ if (flags & O_NONBLOCK) {
+ if (flags & O_EXCL) {
+ if (sdp->open_cnt > 0) {
+ retval = -EBUSY;
+ goto error_mutex_locked;
+ }
+ } else {
+ if (sdp->exclude) {
+ retval = -EBUSY;
+ goto error_mutex_locked;
+ }
}
+ } else {
+ retval = open_wait(sdp, flags);
+ if (retval) /* -ERESTARTSYS or -ENODEV */
+ goto error_mutex_locked;
}
- if (sdp->detached) {
- retval = -ENODEV;
- goto error_out;
- }
- if (sfds_list_empty(sdp)) { /* no existing opens on this device */
+
+ /* N.B. at this point we are holding the open_rel_lock */
+ if (flags & O_EXCL)
+ sdp->exclude = true;
+
+ if (sdp->open_cnt < 1) { /* no existing opens */
sdp->sgdebug = 0;
q = sdp->device->request_queue;
sdp->sg_tablesize = queue_max_segments(q);
}
- if ((sfp = sg_add_sfp(sdp, dev)))
- filp->private_data = sfp;
- else {
- if (flags & O_EXCL) {
- set_exclude(sdp, 0); /* undo if error */
- wake_up_interruptible(&sdp->o_excl_wait);
- }
- retval = -ENOMEM;
- goto error_out;
+ sfp = sg_add_sfp(sdp, dev);
+ if (IS_ERR(sfp)) {
+ retval = PTR_ERR(sfp);
+ goto out_undo;
}
+
+ filp->private_data = sfp;
+ sdp->open_cnt++;
+ mutex_unlock(&sdp->open_rel_lock);
+
retval = 0;
-error_out:
- if (retval) {
- scsi_autopm_put_device(sdp->device);
-sdp_put:
- scsi_device_put(sdp->device);
- }
sg_put:
- if (sdp)
- sg_put_dev(sdp);
+ kref_put(&sdp->d_ref, sg_device_destroy);
return retval;
+
+out_undo:
+ if (flags & O_EXCL) {
+ sdp->exclude = false; /* undo if error */
+ wake_up_interruptible(&sdp->open_wait);
+ }
+error_mutex_locked:
+ mutex_unlock(&sdp->open_rel_lock);
+error_out:
+ scsi_autopm_put_device(sdp->device);
+sdp_put:
+ scsi_device_put(sdp->device);
+ goto sg_put;
}
-/* Following function was formerly called 'sg_close' */
+/* Release resources associated with a successful sg_open()
+ * Returns 0 on success, else a negated errno value */
static int
sg_release(struct inode *inode, struct file *filp)
{
@@ -363,11 +368,20 @@ sg_release(struct inode *inode, struct file *filp)
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
- set_exclude(sdp, 0);
- wake_up_interruptible(&sdp->o_excl_wait);
-
+ mutex_lock(&sdp->open_rel_lock);
scsi_autopm_put_device(sdp->device);
kref_put(&sfp->f_ref, sg_remove_sfp);
+ sdp->open_cnt--;
+
+ /* possibly many open()s waiting on exlude clearing, start many;
+ * only open(O_EXCL)s wait on 0==open_cnt so only start one */
+ if (sdp->exclude) {
+ sdp->exclude = false;
+ wake_up_interruptible_all(&sdp->open_wait);
+ } else if (0 == sdp->open_cnt) {
+ wake_up_interruptible(&sdp->open_wait);
+ }
+ mutex_unlock(&sdp->open_rel_lock);
return 0;
}
@@ -419,7 +433,7 @@ sg_read(struct file *filp, char __user *buf, size_t count,
loff_t * ppos)
}
srp = sg_get_rq_mark(sfp, req_pack_id);
if (!srp) { /* now wait on packet to arrive */
- if (sdp->detached) {
+ if (atomic_read(&sdp->detaching)) {
retval = -ENODEV;
goto free_old_hdr;
}
@@ -428,9 +442,9 @@ sg_read(struct file *filp, char __user *buf, size_t count,
loff_t * ppos)
goto free_old_hdr;
}
retval = wait_event_interruptible(sfp->read_wait,
- (sdp->detached ||
+ (atomic_read(&sdp->detaching) ||
(srp = sg_get_rq_mark(sfp, req_pack_id))));
- if (sdp->detached) {
+ if (atomic_read(&sdp->detaching)) {
retval = -ENODEV;
goto free_old_hdr;
}
@@ -572,7 +586,7 @@ sg_write(struct file *filp, const char __user *buf, size_t
count, loff_t * ppos)
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
sdp->disk->disk_name, (int) count));
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
if (!((filp->f_flags & O_NONBLOCK) ||
scsi_block_when_processing_errors(sdp->device)))
@@ -764,7 +778,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp,
sg_finish_rem_req(srp);
return k; /* probably out of space --> ENOMEM */
}
- if (sdp->detached) {
+ if (atomic_read(&sdp->detaching)) {
if (srp->bio)
blk_end_request_all(srp->rq, -EIO);
sg_finish_rem_req(srp);
@@ -826,7 +840,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned
long arg)
switch (cmd_in) {
case SG_IO:
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
if (!scsi_block_when_processing_errors(sdp->device))
return -ENXIO;
@@ -837,8 +851,8 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned
long arg)
if (result < 0)
return result;
result = wait_event_interruptible(sfp->read_wait,
- (srp_done(sfp, srp) || sdp->detached));
- if (sdp->detached)
+ (srp_done(sfp, srp) || atomic_read(&sdp->detaching)));
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
write_lock_irq(&sfp->rq_list_lock);
if (srp->done) {
@@ -877,7 +891,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned
long arg)
sg_build_reserve(sfp, val);
}
} else {
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
sfp->low_dma = sdp->device->host->unchecked_isa_dma;
}
@@ -890,7 +904,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned
long arg)
else {
sg_scsi_id_t __user *sg_idp = p;
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
__put_user((int) sdp->device->host->host_no,
&sg_idp->host_no);
@@ -1032,11 +1046,11 @@ sg_ioctl(struct file *filp, unsigned int cmd_in,
unsigned long arg)
return result;
}
case SG_EMULATED_HOST:
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
return put_user(sdp->device->host->hostt->emulated, ip);
case SG_SCSI_RESET:
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
if (filp->f_flags & O_NONBLOCK) {
if (scsi_host_in_recovery(sdp->device->host))
@@ -1069,7 +1083,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned
long arg)
return (scsi_reset_provider(sdp->device, val) ==
SUCCESS) ? 0 : -EIO;
case SCSI_IOCTL_SEND_COMMAND:
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
if (read_only) {
unsigned char opcode = WRITE_6;
@@ -1091,7 +1105,7 @@ sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned
long arg)
case SCSI_IOCTL_GET_BUS_NUMBER:
case SCSI_IOCTL_PROBE_HOST:
case SG_GET_TRANSFORM:
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
return -ENODEV;
return scsi_ioctl(sdp->device, cmd_in, p);
case BLKSECTGET:
@@ -1165,7 +1179,7 @@ sg_poll(struct file *filp, poll_table * wait)
}
read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
- if (sdp->detached)
+ if (atomic_read(&sdp->detaching))
res |= POLLHUP;
else if (!sfp->cmd_q) {
if (0 == count)
@@ -1264,7 +1278,8 @@ sg_mmap(struct file *filp, struct vm_area_struct *vma)
return 0;
}
-static void sg_rq_end_io_usercontext(struct work_struct *work)
+static void
+sg_rq_end_io_usercontext(struct work_struct *work)
{
struct sg_request *srp = container_of(work, struct sg_request, ew.work);
struct sg_fd *sfp = srp->parentfp;
@@ -1277,7 +1292,8 @@ static void sg_rq_end_io_usercontext(struct work_struct
*work)
* This function is a "bottom half" handler that is called by the mid
* level when a command is completed (or has failed).
*/
-static void sg_rq_end_io(struct request *rq, int uptodate)
+static void
+sg_rq_end_io(struct request *rq, int uptodate)
{
struct sg_request *srp = rq->end_io_data;
Sg_device *sdp;
@@ -1295,8 +1311,8 @@ static void sg_rq_end_io(struct request *rq, int uptodate)
return;
sdp = sfp->parentdp;
- if (unlikely(sdp->detached))
- printk(KERN_INFO "sg_rq_end_io: device detached\n");
+ if (unlikely(atomic_read(&sdp->detaching)))
+ pr_info("%s: device detaching\n", __func__);
sense = rq->sense;
result = rq->errors;
@@ -1319,7 +1335,7 @@ static void sg_rq_end_io(struct request *rq, int uptodate)
if ((sdp->sgdebug > 0) &&
((CHECK_CONDITION == srp->header.masked_status) ||
(COMMAND_TERMINATED == srp->header.masked_status)))
- __scsi_print_sense("sg_cmd_done", sense,
+ __scsi_print_sense(__func__, sense,
SCSI_SENSE_BUFFERSIZE);
/* Following if statement is a patch supplied by Eric Youngdale
*/
@@ -1378,7 +1394,8 @@ static struct class *sg_sysfs_class;
static int sg_sysfs_valid = 0;
-static Sg_device *sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
+static Sg_device *
+sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
{
struct request_queue *q = scsidp->request_queue;
Sg_device *sdp;
@@ -1388,7 +1405,8 @@ static Sg_device *sg_alloc(struct gendisk *disk, struct
scsi_device *scsidp)
sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
if (!sdp) {
- printk(KERN_WARNING "kmalloc Sg_device failure\n");
+ sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
+ "failure\n", __func__);
return ERR_PTR(-ENOMEM);
}
@@ -1403,8 +1421,9 @@ static Sg_device *sg_alloc(struct gendisk *disk, struct
scsi_device *scsidp)
scsidp->type, SG_MAX_DEVS - 1);
error = -ENODEV;
} else {
- printk(KERN_WARNING
- "idr allocation Sg_device failure: %d\n", error);
+ sdev_printk(KERN_WARNING, scsidp, "%s: idr "
+ "allocation Sg_device failure: %d\n",
+ __func__, error);
}
goto out_unlock;
}
@@ -1415,8 +1434,11 @@ static Sg_device *sg_alloc(struct gendisk *disk, struct
scsi_device *scsidp)
disk->first_minor = k;
sdp->disk = disk;
sdp->device = scsidp;
+ mutex_init(&sdp->open_rel_lock);
INIT_LIST_HEAD(&sdp->sfds);
- init_waitqueue_head(&sdp->o_excl_wait);
+ init_waitqueue_head(&sdp->open_wait);
+ atomic_set(&sdp->detaching, 0);
+ rwlock_init(&sdp->sfd_lock);
sdp->sg_tablesize = queue_max_segments(q);
sdp->index = k;
kref_init(&sdp->d_ref);
@@ -1434,7 +1456,7 @@ out_unlock:
}
static int
-sg_add(struct device *cl_dev, struct class_interface *cl_intf)
+sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)
{
struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
struct gendisk *disk;
@@ -1445,7 +1467,7 @@ sg_add(struct device *cl_dev, struct class_interface
*cl_intf)
disk = alloc_disk(1);
if (!disk) {
- printk(KERN_WARNING "alloc_disk failed\n");
+ pr_warn("%s: alloc_disk failed\n", __func__);
return -ENOMEM;
}
disk->major = SCSI_GENERIC_MAJOR;
@@ -1453,7 +1475,7 @@ sg_add(struct device *cl_dev, struct class_interface
*cl_intf)
error = -ENOMEM;
cdev = cdev_alloc();
if (!cdev) {
- printk(KERN_WARNING "cdev_alloc failed\n");
+ pr_warn("%s: cdev_alloc failed\n", __func__);
goto out;
}
cdev->owner = THIS_MODULE;
@@ -1461,7 +1483,7 @@ sg_add(struct device *cl_dev, struct class_interface
*cl_intf)
sdp = sg_alloc(disk, scsidp);
if (IS_ERR(sdp)) {
- printk(KERN_WARNING "sg_alloc failed\n");
+ pr_warn("%s: sg_alloc failed\n", __func__);
error = PTR_ERR(sdp);
goto out;
}
@@ -1479,22 +1501,20 @@ sg_add(struct device *cl_dev, struct class_interface
*cl_intf)
sdp->index),
sdp, "%s", disk->disk_name);
if (IS_ERR(sg_class_member)) {
- printk(KERN_ERR "sg_add: "
- "device_create failed\n");
+ pr_err("%s: device_create failed\n", __func__);
error = PTR_ERR(sg_class_member);
goto cdev_add_err;
}
error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
&sg_class_member->kobj, "generic");
if (error)
- printk(KERN_ERR "sg_add: unable to make symlink "
- "'generic' back to sg%d\n", sdp->index);
+ pr_err("%s: unable to make symlink 'generic' back "
+ "to sg%d\n", __func__, sdp->index);
} else
- printk(KERN_WARNING "sg_add: sg_sys Invalid\n");
+ pr_warn("%s: sg_sys Invalid\n", __func__);
- sdev_printk(KERN_NOTICE, scsidp,
- "Attached scsi generic sg%d type %d\n", sdp->index,
- scsidp->type);
+ sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
+ "type %d\n", sdp->index, scsidp->type);
dev_set_drvdata(cl_dev, sdp);
@@ -1513,7 +1533,8 @@ out:
return error;
}
-static void sg_device_destroy(struct kref *kref)
+static void
+sg_device_destroy(struct kref *kref)
{
struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
unsigned long flags;
@@ -1535,33 +1556,39 @@ static void sg_device_destroy(struct kref *kref)
kfree(sdp);
}
-static void sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
+static void
+sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf)
{
struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
Sg_device *sdp = dev_get_drvdata(cl_dev);
unsigned long iflags;
Sg_fd *sfp;
+ int val;
- if (!sdp || sdp->detached)
+ if (!sdp)
return;
+ /* want sdp->detaching non-zero as soon as possible */
+ val = atomic_inc_return(&sdp->detaching);
+ if (val > 1)
+ return; /* only want to do following once per device */
- SCSI_LOG_TIMEOUT(3, printk("sg_remove: %s\n", sdp->disk->disk_name));
+ SCSI_LOG_TIMEOUT(3, printk("%s: %s\n", __func__,
+ sdp->disk->disk_name));
- /* Need a write lock to set sdp->detached. */
- write_lock_irqsave(&sg_index_lock, iflags);
- sdp->detached = 1;
+ read_lock_irqsave(&sdp->sfd_lock, iflags);
list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
- wake_up_interruptible(&sfp->read_wait);
+ wake_up_interruptible_all(&sfp->read_wait);
kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
}
- write_unlock_irqrestore(&sg_index_lock, iflags);
+ wake_up_interruptible_all(&sdp->open_wait);
+ read_unlock_irqrestore(&sdp->sfd_lock, iflags);
sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
cdev_del(sdp->cdev);
sdp->cdev = NULL;
- sg_put_dev(sdp);
+ kref_put(&sdp->d_ref, sg_device_destroy);
}
module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
@@ -1631,7 +1658,8 @@ exit_sg(void)
idr_destroy(&sg_index_idr);
}
-static int sg_start_req(Sg_request *srp, unsigned char *cmd)
+static int
+sg_start_req(Sg_request *srp, unsigned char *cmd)
{
int res;
struct request *rq;
@@ -1726,7 +1754,8 @@ static int sg_start_req(Sg_request *srp, unsigned char
*cmd)
return res;
}
-static int sg_finish_rem_req(Sg_request * srp)
+static int
+sg_finish_rem_req(Sg_request *srp)
{
int ret = 0;
@@ -2063,7 +2092,7 @@ sg_add_sfp(Sg_device * sdp, int dev)
sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
if (!sfp)
- return NULL;
+ return ERR_PTR(-ENOMEM);
init_waitqueue_head(&sfp->read_wait);
rwlock_init(&sfp->rq_list_lock);
@@ -2077,9 +2106,13 @@ sg_add_sfp(Sg_device * sdp, int dev)
sfp->cmd_q = SG_DEF_COMMAND_Q;
sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
sfp->parentdp = sdp;
- write_lock_irqsave(&sg_index_lock, iflags);
+ write_lock_irqsave(&sdp->sfd_lock, iflags);
+ if (atomic_read(&sdp->detaching)) {
+ write_unlock_irqrestore(&sdp->sfd_lock, iflags);
+ return ERR_PTR(-ENODEV);
+ }
list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
- write_unlock_irqrestore(&sg_index_lock, iflags);
+ write_unlock_irqrestore(&sdp->sfd_lock, iflags);
SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
if (unlikely(sg_big_buff != def_reserved_size))
sg_big_buff = def_reserved_size;
@@ -2095,7 +2128,8 @@ sg_add_sfp(Sg_device * sdp, int dev)
return sfp;
}
-static void sg_remove_sfp_usercontext(struct work_struct *work)
+static void
+sg_remove_sfp_usercontext(struct work_struct *work)
{
struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
struct sg_device *sdp = sfp->parentdp;
@@ -2119,20 +2153,20 @@ static void sg_remove_sfp_usercontext(struct
work_struct *work)
kfree(sfp);
scsi_device_put(sdp->device);
- sg_put_dev(sdp);
+ kref_put(&sdp->d_ref, sg_device_destroy);
module_put(THIS_MODULE);
}
-static void sg_remove_sfp(struct kref *kref)
+static void
+sg_remove_sfp(struct kref *kref)
{
struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
struct sg_device *sdp = sfp->parentdp;
unsigned long iflags;
- write_lock_irqsave(&sg_index_lock, iflags);
+ write_lock_irqsave(&sdp->sfd_lock, iflags);
list_del(&sfp->sfd_siblings);
- write_unlock_irqrestore(&sg_index_lock, iflags);
- wake_up_interruptible(&sdp->o_excl_wait);
+ write_unlock_irqrestore(&sdp->sfd_lock, iflags);
INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
schedule_work(&sfp->ew.work);
@@ -2183,7 +2217,8 @@ static Sg_device *sg_lookup_dev(int dev)
return idr_find(&sg_index_idr, dev);
}
-static Sg_device *sg_get_dev(int dev)
+static Sg_device *
+sg_get_dev(int dev)
{
struct sg_device *sdp;
unsigned long flags;
@@ -2192,8 +2227,8 @@ static Sg_device *sg_get_dev(int dev)
sdp = sg_lookup_dev(dev);
if (!sdp)
sdp = ERR_PTR(-ENXIO);
- else if (sdp->detached) {
- /* If sdp->detached, then the refcount may already be 0, in
+ else if (atomic_read(&sdp->detaching)) {
+ /* If sdp->detaching, then the refcount may already be 0, in
* which case it would be a bug to do kref_get().
*/
sdp = ERR_PTR(-ENODEV);
@@ -2204,11 +2239,6 @@ static Sg_device *sg_get_dev(int dev)
return sdp;
}
-static void sg_put_dev(struct sg_device *sdp)
-{
- kref_put(&sdp->d_ref, sg_device_destroy);
-}
-
#ifdef CONFIG_SCSI_PROC_FS
static struct proc_dir_entry *sg_proc_sgp = NULL;
@@ -2425,8 +2455,7 @@ static int sg_proc_single_open_version(struct inode
*inode, struct file *file)
static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
{
- seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
- "online\n");
+ seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
return 0;
}
@@ -2482,7 +2511,11 @@ static int sg_proc_seq_show_dev(struct seq_file *s, void
*v)
read_lock_irqsave(&sg_index_lock, iflags);
sdp = it ? sg_lookup_dev(it->index) : NULL;
- if (sdp && (scsidp = sdp->device) && (!sdp->detached))
+ if ((NULL == sdp) || (NULL == sdp->device) ||
+ (atomic_read(&sdp->detaching)))
+ seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
+ else {
+ scsidp = sdp->device;
seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
scsidp->host->host_no, scsidp->channel,
scsidp->id, scsidp->lun, (int) scsidp->type,
@@ -2490,8 +2523,7 @@ static int sg_proc_seq_show_dev(struct seq_file *s, void
*v)
(int) scsidp->queue_depth,
(int) atomic_read(&scsidp->device_busy),
(int) scsi_device_online(scsidp));
- else
- seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
+ }
read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}
@@ -2510,11 +2542,12 @@ static int sg_proc_seq_show_devstrs(struct seq_file *s,
void *v)
read_lock_irqsave(&sg_index_lock, iflags);
sdp = it ? sg_lookup_dev(it->index) : NULL;
- if (sdp && (scsidp = sdp->device) && (!sdp->detached))
+ scsidp = sdp ? sdp->device : NULL;
+ if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
scsidp->vendor, scsidp->model, scsidp->rev);
else
- seq_printf(s, "<no active device>\n");
+ seq_puts(s, "<no active device>\n");
read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}
@@ -2559,12 +2592,12 @@ static void sg_proc_debug_helper(struct seq_file *s,
Sg_device * sdp)
else
cp = " ";
}
- seq_printf(s, cp);
+ seq_puts(s, cp);
blen = srp->data.bufflen;
usg = srp->data.k_use_sg;
- seq_printf(s, srp->done ?
- ((1 == srp->done) ? "rcv:" : "fin:")
- : "act:");
+ seq_puts(s, srp->done ?
+ ((1 == srp->done) ? "rcv:" : "fin:")
+ : "act:");
seq_printf(s, " id=%d blen=%d",
srp->header.pack_id, blen);
if (srp->done)
@@ -2580,7 +2613,7 @@ static void sg_proc_debug_helper(struct seq_file *s,
Sg_device * sdp)
(int) srp->data.cmd_opcode);
}
if (0 == m)
- seq_printf(s, " No requests active\n");
+ seq_puts(s, " No requests active\n");
read_unlock(&fp->rq_list_lock);
}
}
@@ -2596,31 +2629,34 @@ static int sg_proc_seq_show_debug(struct seq_file *s,
void *v)
Sg_device *sdp;
unsigned long iflags;
- if (it && (0 == it->index)) {
- seq_printf(s, "max_active_device=%d(origin 1)\n",
- (int)it->max);
- seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
- }
+ if (it && (0 == it->index))
+ seq_printf(s, "max_active_device=%d def_reserved_size=%d\n",
+ (int)it->max, sg_big_buff);
read_lock_irqsave(&sg_index_lock, iflags);
sdp = it ? sg_lookup_dev(it->index) : NULL;
- if (sdp && !list_empty(&sdp->sfds)) {
- struct scsi_device *scsidp = sdp->device;
-
+ if (NULL == sdp)
+ goto skip;
+ read_lock(&sdp->sfd_lock);
+ if (!list_empty(&sdp->sfds)) {
seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
- if (sdp->detached)
- seq_printf(s, "detached pending close ");
- else
- seq_printf
- (s, "scsi%d chan=%d id=%d lun=%d em=%d",
- scsidp->host->host_no,
- scsidp->channel, scsidp->id,
- scsidp->lun,
- scsidp->host->hostt->emulated);
- seq_printf(s, " sg_tablesize=%d excl=%d\n",
- sdp->sg_tablesize, get_exclude(sdp));
+ if (atomic_read(&sdp->detaching))
+ seq_puts(s, "detaching pending close ");
+ else if (sdp->device) {
+ struct scsi_device *scsidp = sdp->device;
+
+ seq_printf(s, "%d:%d:%d:%d em=%d",
+ scsidp->host->host_no,
+ scsidp->channel, scsidp->id,
+ scsidp->lun,
+ scsidp->host->hostt->emulated);
+ }
+ seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
+ sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
sg_proc_debug_helper(s, sdp);
}
+ read_unlock(&sdp->sfd_lock);
+skip:
read_unlock_irqrestore(&sg_index_lock, iflags);
return 0;
}
--
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