From 45465487897a1c6d508b14b904dc5777f7ec7e04 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:26 -0800 Subject: kfifo: move struct kfifo in place This is a new generic kernel FIFO implementation. The current kernel fifo API is not very widely used, because it has to many constrains. Only 17 files in the current 2.6.31-rc5 used it. FIFO's are like list's a very basic thing and a kfifo API which handles the most use case would save a lot of development time and memory resources. I think this are the reasons why kfifo is not in use: - The API is to simple, important functions are missing - A fifo can be only allocated dynamically - There is a requirement of a spinlock whether you need it or not - There is no support for data records inside a fifo So I decided to extend the kfifo in a more generic way without blowing up the API to much. The new API has the following benefits: - Generic usage: For kernel internal use and/or device driver. - Provide an API for the most use case. - Slim API: The whole API provides 25 functions. - Linux style habit. - DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros - Direct copy_to_user from the fifo and copy_from_user into the fifo. - The kfifo itself is an in place member of the using data structure, this save an indirection access and does not waste the kernel allocator. - Lockless access: if only one reader and one writer is active on the fifo, which is the common use case, no additional locking is necessary. - Remove spinlock - give the user the freedom of choice what kind of locking to use if one is required. - Ability to handle records. Three type of records are supported: - Variable length records between 0-255 bytes, with a record size field of 1 bytes. - Variable length records between 0-65535 bytes, with a record size field of 2 bytes. - Fixed size records, which no record size field. - Preserve memory resource. - Performance! - Easy to use! This patch: Since most users want to have the kfifo as part of another object, reorganize the code to allow including struct kfifo in another data structure. This requires changing the kfifo_alloc and kfifo_init prototypes so that we pass an existing kfifo pointer into them. This patch changes the implementation and all existing users. [akpm@linux-foundation.org: fix warning] Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/scsi/libsrp.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) (limited to 'drivers/scsi/libsrp.c') diff --git a/drivers/scsi/libsrp.c b/drivers/scsi/libsrp.c index 9ad38e81e343..b1b5e51ca8e3 100644 --- a/drivers/scsi/libsrp.c +++ b/drivers/scsi/libsrp.c @@ -58,19 +58,16 @@ static int srp_iu_pool_alloc(struct srp_queue *q, size_t max, goto free_pool; spin_lock_init(&q->lock); - q->queue = kfifo_init((void *) q->pool, max * sizeof(void *), - GFP_KERNEL, &q->lock); - if (IS_ERR(q->queue)) - goto free_item; + kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *), + &q->lock); for (i = 0, iue = q->items; i < max; i++) { - __kfifo_put(q->queue, (void *) &iue, sizeof(void *)); + __kfifo_put(&q->queue, (void *) &iue, sizeof(void *)); iue->sbuf = ring[i]; iue++; } return 0; -free_item: kfree(q->items); free_pool: kfree(q->pool); @@ -167,7 +164,7 @@ struct iu_entry *srp_iu_get(struct srp_target *target) { struct iu_entry *iue = NULL; - kfifo_get(target->iu_queue.queue, (void *) &iue, sizeof(void *)); + kfifo_get(&target->iu_queue.queue, (void *) &iue, sizeof(void *)); if (!iue) return iue; iue->target = target; @@ -179,7 +176,7 @@ EXPORT_SYMBOL_GPL(srp_iu_get); void srp_iu_put(struct iu_entry *iue) { - kfifo_put(iue->target->iu_queue.queue, (void *) &iue, sizeof(void *)); + kfifo_put(&iue->target->iu_queue.queue, (void *) &iue, sizeof(void *)); } EXPORT_SYMBOL_GPL(srp_iu_put); -- cgit v1.2.3 From c1e13f25674ed564948ecb7dfe5f83e578892896 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:27 -0800 Subject: kfifo: move out spinlock Move the pointer to the spinlock out of struct kfifo. Most users in tree do not actually use a spinlock, so the few exceptions now have to call kfifo_{get,put}_locked, which takes an extra argument to a spinlock. Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/scsi/libsrp.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'drivers/scsi/libsrp.c') diff --git a/drivers/scsi/libsrp.c b/drivers/scsi/libsrp.c index b1b5e51ca8e3..db1b41c55fd3 100644 --- a/drivers/scsi/libsrp.c +++ b/drivers/scsi/libsrp.c @@ -58,8 +58,7 @@ static int srp_iu_pool_alloc(struct srp_queue *q, size_t max, goto free_pool; spin_lock_init(&q->lock); - kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *), - &q->lock); + kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *)); for (i = 0, iue = q->items; i < max; i++) { __kfifo_put(&q->queue, (void *) &iue, sizeof(void *)); @@ -164,7 +163,8 @@ struct iu_entry *srp_iu_get(struct srp_target *target) { struct iu_entry *iue = NULL; - kfifo_get(&target->iu_queue.queue, (void *) &iue, sizeof(void *)); + kfifo_get_locked(&target->iu_queue.queue, (void *) &iue, + sizeof(void *), &target->iu_queue.lock); if (!iue) return iue; iue->target = target; @@ -176,7 +176,8 @@ EXPORT_SYMBOL_GPL(srp_iu_get); void srp_iu_put(struct iu_entry *iue) { - kfifo_put(&iue->target->iu_queue.queue, (void *) &iue, sizeof(void *)); + kfifo_put_locked(&iue->target->iu_queue.queue, (void *) &iue, + sizeof(void *), &iue->target->iu_queue.lock); } EXPORT_SYMBOL_GPL(srp_iu_put); -- cgit v1.2.3 From e64c026dd09b73faf20707711402fc5ed55a8e70 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:28 -0800 Subject: kfifo: cleanup namespace change name of __kfifo_* functions to kfifo_*, because the prefix __kfifo should be reserved for internal functions only. Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/scsi/libsrp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/scsi/libsrp.c') diff --git a/drivers/scsi/libsrp.c b/drivers/scsi/libsrp.c index db1b41c55fd3..975e448cfcb9 100644 --- a/drivers/scsi/libsrp.c +++ b/drivers/scsi/libsrp.c @@ -61,7 +61,7 @@ static int srp_iu_pool_alloc(struct srp_queue *q, size_t max, kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *)); for (i = 0, iue = q->items; i < max; i++) { - __kfifo_put(&q->queue, (void *) &iue, sizeof(void *)); + kfifo_put(&q->queue, (void *) &iue, sizeof(void *)); iue->sbuf = ring[i]; iue++; } -- cgit v1.2.3 From 7acd72eb85f1c7a15e8b5eb554994949241737f1 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:28 -0800 Subject: kfifo: rename kfifo_put... into kfifo_in... and kfifo_get... into kfifo_out... rename kfifo_put... into kfifo_in... to prevent miss use of old non in kernel-tree drivers ditto for kfifo_get... -> kfifo_out... Improve the prototypes of kfifo_in and kfifo_out to make the kerneldoc annotations more readable. Add mini "howto porting to the new API" in kfifo.h Signed-off-by: Stefani Seibold Acked-by: Greg Kroah-Hartman Acked-by: Mauro Carvalho Chehab Acked-by: Andi Kleen Acked-by: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/scsi/libsrp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/scsi/libsrp.c') diff --git a/drivers/scsi/libsrp.c b/drivers/scsi/libsrp.c index 975e448cfcb9..8424b8606efb 100644 --- a/drivers/scsi/libsrp.c +++ b/drivers/scsi/libsrp.c @@ -61,7 +61,7 @@ static int srp_iu_pool_alloc(struct srp_queue *q, size_t max, kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *)); for (i = 0, iue = q->items; i < max; i++) { - kfifo_put(&q->queue, (void *) &iue, sizeof(void *)); + kfifo_in(&q->queue, (void *) &iue, sizeof(void *)); iue->sbuf = ring[i]; iue++; } @@ -163,7 +163,7 @@ struct iu_entry *srp_iu_get(struct srp_target *target) { struct iu_entry *iue = NULL; - kfifo_get_locked(&target->iu_queue.queue, (void *) &iue, + kfifo_out_locked(&target->iu_queue.queue, (void *) &iue, sizeof(void *), &target->iu_queue.lock); if (!iue) return iue; @@ -176,7 +176,7 @@ EXPORT_SYMBOL_GPL(srp_iu_get); void srp_iu_put(struct iu_entry *iue) { - kfifo_put_locked(&iue->target->iu_queue.queue, (void *) &iue, + kfifo_in_locked(&iue->target->iu_queue.queue, (void *) &iue, sizeof(void *), &iue->target->iu_queue.lock); } EXPORT_SYMBOL_GPL(srp_iu_put); -- cgit v1.2.3 From 9842c38e917636fa7dc6b88aff17a8f1fd7f0cc0 Mon Sep 17 00:00:00 2001 From: Stefani Seibold Date: Mon, 21 Dec 2009 14:37:29 -0800 Subject: kfifo: fix warn_unused_result Fix the "ignoring return value of '...', declared with attribute warn_unused_result" compiler warning in several users of the new kfifo API. It removes the __must_check attribute from kfifo_in() and kfifo_in_locked() which must not necessary performed. Fix the allocation bug in the nozomi driver file, by moving out the kfifo_alloc from the interrupt handler into the probe function. Fix the kfifo_out() and kfifo_out_locked() users to handle a unexpected end of fifo. Signed-off-by: Stefani Seibold Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/scsi/libsrp.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'drivers/scsi/libsrp.c') diff --git a/drivers/scsi/libsrp.c b/drivers/scsi/libsrp.c index 8424b8606efb..ab19b3b4be52 100644 --- a/drivers/scsi/libsrp.c +++ b/drivers/scsi/libsrp.c @@ -163,8 +163,11 @@ struct iu_entry *srp_iu_get(struct srp_target *target) { struct iu_entry *iue = NULL; - kfifo_out_locked(&target->iu_queue.queue, (void *) &iue, - sizeof(void *), &target->iu_queue.lock); + if (kfifo_out_locked(&target->iu_queue.queue, (void *) &iue, + sizeof(void *), &target->iu_queue.lock) != sizeof(void *)) { + WARN_ONCE(1, "unexpected fifo state"); + return NULL; + } if (!iue) return iue; iue->target = target; -- cgit v1.2.3