Re: [RFC PATCH 26/32] ide-tape: remove packet command and struct request memory buffers
On Sunday 27 January 2008, Borislav Petkov wrote:
From: Borislav Petkov [EMAIL PROTECTED]
Bart,
this one is rather intrusive so please doublecheck it wrt to kzalloc/kfree
balancing on all the codepaths so that we don't leak memory all over the
place.
I free all the alloc'd pc's and rq's in idetape_end_request() which is called
from the callback idetape_pc_callback() registered with the packet command
struct when creating the respective ATAPI cmd.
I was hoping for re-using requests from the request queue for this purpose
(with help of blk_get_request()/blk_put_request()). Jens, is this OK?
This approach wouldn't have a problem with out-of-memory situations (because
blk_get_request() can wait until free request is available), needs less code
and provides additional benefits (like NUMA-friendly allocations).
When it comes to pc-s: long-term it should be possible to use only request
structure and get rid off them.
---
These buffers were always statically allocated during driver initialization no
matter what. Remove them by allocating GFP_ATOMIC memory on demand. In the
case
of allocation error, we only issue error msg in the *alloc_{pc,rq} thus
postponing
the final error handling and cleanup in their callers. Packet command and
request memory is freed in idetape_end_request() which is at the end of the
request path entered from all the callbacks.
Signed-off-by: Borislav Petkov [EMAIL PROTECTED]
---
drivers/ide/ide-tape.c | 122 ++-
1 files changed, 57 insertions(+), 65 deletions(-)
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 041edcd..3c1a7db 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -105,13 +105,6 @@ enum {
#define IDETAPE_PC_BUFFER_SIZE 256
/*
- * In various places in the driver, we need to allocate storage
- * for packet commands and requests, which will remain valid while
- * we leave the driver to wait for an interrupt or a timeout event.
- */
-#define IDETAPE_PC_STACK (10 + IDETAPE_MAX_PC_RETRIES)
-
-/*
* Some drives (for example, Seagate STT3401A Travan) require a very long
* timeout, because they don't return an interrupt or clear their busy bit
* until after the command completes (even retension commands).
@@ -271,13 +264,6 @@ typedef struct ide_tape_obj {
*/
idetape_pc_t *failed_pc;
- idetape_pc_t pc_stack[IDETAPE_PC_STACK];
- /* Next free packet command storage space */
- int pc_stack_idx;
- struct request rq_stack[IDETAPE_PC_STACK];
- /* We implement a circular array */
- int rq_stack_idx;
-
/*
* DSC polling variables.
*
@@ -669,45 +655,32 @@ static void idetape_update_buffers (idetape_pc_t *pc)
pc-bh = bh;
}
-/*
- * idetape_next_pc_storage returns a pointer to a place in which we can
- * safely store a packet command, even though we intend to leave the
- * driver. A storage space for a maximum of IDETAPE_PC_STACK packet
- * commands is allocated at initialization time.
- */
-static idetape_pc_t *idetape_next_pc_storage (ide_drive_t *drive)
+static idetape_pc_t *ide_tape_alloc_pc(void)
{
- idetape_tape_t *tape = drive-driver_data;
+ idetape_pc_t *pc;
- debug_log(DBG_PCRQ_STACK, pc_stack_index=%d\n, tape-pc_stack_idx);
+ pc = kzalloc(sizeof(idetape_pc_t), GFP_ATOMIC);
+ if (!pc)
+ printk(KERN_ERR ide-tape: %s: memory allocation error.,
+ __func__);
- if (tape-pc_stack_idx == IDETAPE_PC_STACK)
- tape-pc_stack_idx = 0;
- return (tape-pc_stack[tape-pc_stack_idx++]);
+ return pc;
}
/*
- * idetape_next_rq_storage is used along with idetape_next_pc_storage.
- * Since we queue packet commands in the request queue, we need to
- * allocate a request, along with the allocation of a packet command.
+ * Since we queue packet commands in the request queue, we need to allocate a
+ * request, along with a packet command.
*/
-
-/**
- **
- * This should get fixed to use kmalloc(.., GFP_ATOMIC) *
- * followed later on by kfree(). -ml *
- **
- **/
-
-static struct request *idetape_next_rq_storage (ide_drive_t *drive)
+static struct request *ide_tape_alloc_rq(void)
{
- idetape_tape_t *tape = drive-driver_data;
+ struct request *rq;
- debug_log(DBG_PCRQ_STACK, rq_stack_index=%d\n, tape-rq_stack_idx);
+ rq = kzalloc(sizeof(struct request), GFP_ATOMIC);
+ if (!rq)
+ printk(KERN_ERR ide-tape: %s: memory allocation error.,
+ __func__);
- if (tape-rq_stack_idx
[RFC PATCH 26/32] ide-tape: remove packet command and struct request memory buffers
From: Borislav Petkov [EMAIL PROTECTED]
Bart,
this one is rather intrusive so please doublecheck it wrt to kzalloc/kfree
balancing on all the codepaths so that we don't leak memory all over the place.
I free all the alloc'd pc's and rq's in idetape_end_request() which is called
from the callback idetape_pc_callback() registered with the packet command
struct when creating the respective ATAPI cmd.
---
These buffers were always statically allocated during driver initialization no
matter what. Remove them by allocating GFP_ATOMIC memory on demand. In the case
of allocation error, we only issue error msg in the *alloc_{pc,rq} thus
postponing
the final error handling and cleanup in their callers. Packet command and
request memory is freed in idetape_end_request() which is at the end of the
request path entered from all the callbacks.
Signed-off-by: Borislav Petkov [EMAIL PROTECTED]
---
drivers/ide/ide-tape.c | 122 ++-
1 files changed, 57 insertions(+), 65 deletions(-)
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 041edcd..3c1a7db 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -105,13 +105,6 @@ enum {
#define IDETAPE_PC_BUFFER_SIZE 256
/*
- * In various places in the driver, we need to allocate storage
- * for packet commands and requests, which will remain valid while
- * we leave the driver to wait for an interrupt or a timeout event.
- */
-#define IDETAPE_PC_STACK (10 + IDETAPE_MAX_PC_RETRIES)
-
-/*
* Some drives (for example, Seagate STT3401A Travan) require a very long
* timeout, because they don't return an interrupt or clear their busy bit
* until after the command completes (even retension commands).
@@ -271,13 +264,6 @@ typedef struct ide_tape_obj {
*/
idetape_pc_t *failed_pc;
- idetape_pc_t pc_stack[IDETAPE_PC_STACK];
- /* Next free packet command storage space */
- int pc_stack_idx;
- struct request rq_stack[IDETAPE_PC_STACK];
- /* We implement a circular array */
- int rq_stack_idx;
-
/*
* DSC polling variables.
*
@@ -669,45 +655,32 @@ static void idetape_update_buffers (idetape_pc_t *pc)
pc-bh = bh;
}
-/*
- * idetape_next_pc_storage returns a pointer to a place in which we can
- * safely store a packet command, even though we intend to leave the
- * driver. A storage space for a maximum of IDETAPE_PC_STACK packet
- * commands is allocated at initialization time.
- */
-static idetape_pc_t *idetape_next_pc_storage (ide_drive_t *drive)
+static idetape_pc_t *ide_tape_alloc_pc(void)
{
- idetape_tape_t *tape = drive-driver_data;
+ idetape_pc_t *pc;
- debug_log(DBG_PCRQ_STACK, pc_stack_index=%d\n, tape-pc_stack_idx);
+ pc = kzalloc(sizeof(idetape_pc_t), GFP_ATOMIC);
+ if (!pc)
+ printk(KERN_ERR ide-tape: %s: memory allocation error.,
+ __func__);
- if (tape-pc_stack_idx == IDETAPE_PC_STACK)
- tape-pc_stack_idx = 0;
- return (tape-pc_stack[tape-pc_stack_idx++]);
+ return pc;
}
/*
- * idetape_next_rq_storage is used along with idetape_next_pc_storage.
- * Since we queue packet commands in the request queue, we need to
- * allocate a request, along with the allocation of a packet command.
+ * Since we queue packet commands in the request queue, we need to allocate a
+ * request, along with a packet command.
*/
-
-/**
- **
- * This should get fixed to use kmalloc(.., GFP_ATOMIC) *
- * followed later on by kfree(). -ml *
- **
- **/
-
-static struct request *idetape_next_rq_storage (ide_drive_t *drive)
+static struct request *ide_tape_alloc_rq(void)
{
- idetape_tape_t *tape = drive-driver_data;
+ struct request *rq;
- debug_log(DBG_PCRQ_STACK, rq_stack_index=%d\n, tape-rq_stack_idx);
+ rq = kzalloc(sizeof(struct request), GFP_ATOMIC);
+ if (!rq)
+ printk(KERN_ERR ide-tape: %s: memory allocation error.,
+ __func__);
- if (tape-rq_stack_idx == IDETAPE_PC_STACK)
- tape-rq_stack_idx = 0;
- return (tape-rq_stack[tape-rq_stack_idx++]);
+ return rq;
}
/*
@@ -981,9 +954,8 @@ static int idetape_end_request(ide_drive_t *drive, int
uptodate, int nr_sects)
}
}
ide_end_drive_cmd(drive, 0, 0);
-// blkdev_dequeue_request(rq);
-// drive-rq = NULL;
-// end_that_request_last(rq);
+ kfree(tape-pc);
+ kfree(rq);
if (remove_stage)
idetape_remove_stage_head(drive);
@@ -1032,13 +1004,9 @@ static void
