Author: hselasky
Date: Fri Apr 17 07:07:06 2015
New Revision: 281644
URL: https://svnweb.freebsd.org/changeset/base/281644
Log:
Buffers which can be memory mapped into userspace should never be
freed. Recycle the buffers instead. This patch also fixes a panic at
reboot issue when an UDL adapter is attached to the system.
Modified:
head/sys/dev/usb/video/udl.c
head/sys/dev/usb/video/udl.h
Modified: head/sys/dev/usb/video/udl.c
==============================================================================
--- head/sys/dev/usb/video/udl.c Fri Apr 17 06:39:15 2015
(r281643)
+++ head/sys/dev/usb/video/udl.c Fri Apr 17 07:07:06 2015
(r281644)
@@ -76,6 +76,11 @@ static int udl_fps = 25;
SYSCTL_INT(_hw_usb_udl, OID_AUTO, fps, CTLFLAG_RWTUN,
&udl_fps, 0, "Frames Per Second, 1-60");
+static struct mtx udl_buffer_mtx;
+static struct udl_buffer_head udl_buffer_head;
+
+MALLOC_DEFINE(M_USB_DL, "USB", "USB DisplayLink");
+
/*
* Prototypes.
*/
@@ -175,6 +180,56 @@ static const STRUCT_USB_HOST_ID udl_devs
{USB_VPI(USB_VENDOR_DISPLAYLINK, USB_PRODUCT_DISPLAYLINK_LT1421, DLUNK)}
};
+static void
+udl_buffer_init(void *arg)
+{
+ mtx_init(&udl_buffer_mtx, "USB", "UDL", MTX_DEF);
+ TAILQ_INIT(&udl_buffer_head);
+}
+SYSINIT(udl_buffer_init, SI_SUB_LOCK, SI_ORDER_FIRST, udl_buffer_init, NULL);
+
+CTASSERT(sizeof(struct udl_buffer) < PAGE_SIZE);
+
+static void *
+udl_buffer_alloc(uint32_t size)
+{
+ struct udl_buffer *buf;
+ mtx_lock(&udl_buffer_mtx);
+ TAILQ_FOREACH(buf, &udl_buffer_head, entry) {
+ if (buf->size == size) {
+ TAILQ_REMOVE(&udl_buffer_head, buf, entry);
+ break;
+ }
+ }
+ mtx_unlock(&udl_buffer_mtx);
+ if (buf != NULL) {
+ /* wipe and recycle buffer */
+ memset(buf, 0, size);
+ return (buf);
+ }
+ /* allocate new buffer */
+ return (malloc(size, M_USB_DL, M_WAITOK | M_ZERO));
+}
+
+static void
+udl_buffer_free(void *_buf, uint32_t size)
+{
+ struct udl_buffer *buf;
+
+ buf = (struct udl_buffer *)_buf;
+ if (buf == NULL)
+ return;
+
+ /*
+ * Memory mapped buffers should never be freed.
+ * Put display buffer into a recycle list.
+ */
+ mtx_lock(&udl_buffer_mtx);
+ buf->size = size;
+ TAILQ_INSERT_TAIL(&udl_buffer_head, buf, entry);
+ mtx_unlock(&udl_buffer_mtx);
+}
+
static uint32_t
udl_get_fb_size(struct udl_softc *sc)
{
@@ -403,11 +458,11 @@ udl_detach(device_t dev)
mtx_destroy(&sc->sc_mtx);
cv_destroy(&sc->sc_cv);
- /*
- * Free framebuffer memory, if any.
- */
- free(sc->sc_fb_addr, M_DEVBUF);
- free(sc->sc_fb_copy, M_DEVBUF);
+ /* put main framebuffer into a recycle list, if any */
+ udl_buffer_free(sc->sc_fb_addr, sc->sc_fb_size);
+
+ /* free shadow framebuffer memory, if any */
+ free(sc->sc_fb_copy, M_USB_DL);
return (0);
}
@@ -782,13 +837,15 @@ udl_fbmem_alloc(struct udl_softc *sc)
size = udl_get_fb_size(sc);
size = round_page(size);
-
+ /* check for zero size */
+ if (size == 0)
+ size = PAGE_SIZE;
/*
* It is assumed that allocations above PAGE_SIZE bytes will
* be PAGE_SIZE aligned for use with mmap()
*/
- sc->sc_fb_addr = malloc(size, M_DEVBUF, M_WAITOK | M_ZERO);
- sc->sc_fb_copy = malloc(size, M_DEVBUF, M_WAITOK | M_ZERO);
+ sc->sc_fb_addr = udl_buffer_alloc(size);
+ sc->sc_fb_copy = malloc(size, M_USB_DL, M_WAITOK | M_ZERO);
sc->sc_fb_size = size;
}
Modified: head/sys/dev/usb/video/udl.h
==============================================================================
--- head/sys/dev/usb/video/udl.h Fri Apr 17 06:39:15 2015
(r281643)
+++ head/sys/dev/usb/video/udl.h Fri Apr 17 07:07:06 2015
(r281644)
@@ -34,6 +34,15 @@
#define UDL_FONT_HEIGHT 16 /* pixels */
#define UDL_MAX_MODES 25 /* units */
+MALLOC_DECLARE(M_USB_DL);
+
+struct udl_buffer {
+ TAILQ_ENTRY(udl_buffer) entry;
+ uint32_t size;
+};
+
+TAILQ_HEAD(udl_buffer_head, udl_buffer);
+
struct udl_cmd_buf {
TAILQ_ENTRY(udl_cmd_buf) entry;
uint32_t off;
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