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authorNaohiro Aota <naota@elisp.net>2010-10-26 14:23:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-26 16:52:18 -0700
commit066a9be6c0124edc9527088231f03c6236be375d (patch)
tree49350239a1505bb08ed67a19ad2a15466f7b7526 /lib/idr.c
parent66f1991bc2357436498ac990302b6f5bf403d7ef (diff)
downloadlinux-linaro-precise-066a9be6c0124edc9527088231f03c6236be375d.tar.gz
idr: fix idr_pre_get() locking description
Despite the idr_pre_get() kernel-doc, there are some cases where you can call idr_pre_get() from within locked regions. Add a description for such cases. See also: http://lkml.org/lkml/2010/9/16/462 [akpm@linux-foundation.org: cleanups, grammatical fixes] Signed-off-by: Naohiro Aota <naota@elisp.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/idr.c')
-rw-r--r--lib/idr.c24
1 files changed, 13 insertions, 11 deletions
diff --git a/lib/idr.c b/lib/idr.c
index 5e0966be0f7..e35850d3004 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -110,9 +110,10 @@ static void idr_mark_full(struct idr_layer **pa, int id)
* @idp: idr handle
* @gfp_mask: memory allocation flags
*
- * This function should be called prior to locking and calling the
- * idr_get_new* functions. It preallocates enough memory to satisfy
- * the worst possible allocation.
+ * This function should be called prior to calling the idr_get_new* functions.
+ * It preallocates enough memory to satisfy the worst possible allocation. The
+ * caller should pass in GFP_KERNEL if possible. This of course requires that
+ * no spinning locks be held.
*
* If the system is REALLY out of memory this function returns 0,
* otherwise 1.
@@ -290,9 +291,11 @@ static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id)
* This is the allocate id function. It should be called with any
* required locks.
*
- * If memory is required, it will return -EAGAIN, you should unlock
- * and go back to the idr_pre_get() call. If the idr is full, it will
- * return -ENOSPC.
+ * If allocation from IDR's private freelist fails, idr_get_new_above() will
+ * return -EAGAIN. The caller should retry the idr_pre_get() call to refill
+ * IDR's preallocation and then retry the idr_get_new_above() call.
+ *
+ * If the idr is full idr_get_new_above() will return -ENOSPC.
*
* @id returns a value in the range @starting_id ... 0x7fffffff
*/
@@ -318,12 +321,11 @@ EXPORT_SYMBOL(idr_get_new_above);
* @ptr: pointer you want associated with the id
* @id: pointer to the allocated handle
*
- * This is the allocate id function. It should be called with any
- * required locks.
+ * If allocation from IDR's private freelist fails, idr_get_new_above() will
+ * return -EAGAIN. The caller should retry the idr_pre_get() call to refill
+ * IDR's preallocation and then retry the idr_get_new_above() call.
*
- * If memory is required, it will return -EAGAIN, you should unlock
- * and go back to the idr_pre_get() call. If the idr is full, it will
- * return -ENOSPC.
+ * If the idr is full idr_get_new_above() will return -ENOSPC.
*
* @id returns a value in the range 0 ... 0x7fffffff
*/