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authorJeff Dike <jdike@addtoit.com>2007-03-29 01:20:27 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-03-29 08:22:24 -0700
commit2a9529a0c890007ade5425b75272c3def283f8b1 (patch)
tree964576fad2872f41e798e109979daad4002007af /arch
parentcb3fecc2f29056e89658e7eb371e7f9be66cda6d (diff)
[PATCH] uml: fix I/O hang when multiple devices are in use
Commit 62f96cb01e8de7a5daee472e540f726db2801499 introduced per-devices queues and locks, which was fine as far as it went, but left in place a global which controlled access to submitting requests to the host. This should have been made per-device as well, since it causes I/O hangs when multiple block devices are in use. This patch fixes that by replacing the global with an activity flag in the device structure in order to tell whether the queue is currently being run. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/um/drivers/ubd_kern.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index f98d26e5138..8bd9204ac1a 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -109,10 +109,6 @@ static inline void ubd_set_bit(__u64 bit, unsigned char *data)
static DEFINE_MUTEX(ubd_lock);
-/* XXX - this made sense in 2.4 days, now it's only used as a boolean, and
- * probably it doesn't make sense even for that. */
-static int do_ubd;
-
static int ubd_open(struct inode * inode, struct file * filp);
static int ubd_release(struct inode * inode, struct file * file);
static int ubd_ioctl(struct inode * inode, struct file * file,
@@ -169,6 +165,7 @@ struct ubd {
struct platform_device pdev;
struct request_queue *queue;
spinlock_t lock;
+ int active;
};
#define DEFAULT_COW { \
@@ -190,6 +187,7 @@ struct ubd {
.shared = 0, \
.cow = DEFAULT_COW, \
.lock = SPIN_LOCK_UNLOCKED, \
+ .active = 0, \
}
/* Protected by ubd_lock */
@@ -507,7 +505,6 @@ static void ubd_handler(void)
struct ubd *dev;
int n;
- do_ubd = 0;
n = os_read_file(thread_fd, &req, sizeof(req));
if(n != sizeof(req)){
printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, "
@@ -517,6 +514,7 @@ static void ubd_handler(void)
rq = req.req;
dev = rq->rq_disk->private_data;
+ dev->active = 0;
ubd_finish(rq, req.error);
reactivate_fd(thread_fd, UBD_IRQ);
@@ -1081,11 +1079,12 @@ static void do_ubd_request(request_queue_t *q)
}
}
else {
- if(do_ubd || (req = elv_next_request(q)) == NULL)
+ struct ubd *dev = q->queuedata;
+ if(dev->active || (req = elv_next_request(q)) == NULL)
return;
err = prepare_request(req, &io_req);
if(!err){
- do_ubd = 1;
+ dev->active = 1;
n = os_write_file(thread_fd, (char *) &io_req,
sizeof(io_req));
if(n != sizeof(io_req))