From b32d45824aa7e07a0c3257a16e3a2a691b11b39a Mon Sep 17 00:00:00 2001 From: Nathan Huckleberry Date: Fri, 22 Jul 2022 09:38:22 +0000 Subject: dm bufio: Add DM_BUFIO_CLIENT_NO_SLEEP flag Add an optional flag that ensures dm_bufio_client does not sleep (primary focus is to service dm_bufio_get without sleeping). This allows the dm-bufio cache to be queried from interrupt context. To ensure that dm-bufio does not sleep, dm-bufio must use a spinlock instead of a mutex. Additionally, to avoid deadlocks, special care must be taken so that dm-bufio does not sleep while holding the spinlock. But again: the scope of this no_sleep is initially confined to dm_bufio_get, so __alloc_buffer_wait_no_callback is _not_ changed to avoid sleeping because __bufio_new avoids allocation for NF_GET. Signed-off-by: Nathan Huckleberry Signed-off-by: Mike Snitzer --- include/linux/dm-bufio.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/dm-bufio.h') diff --git a/include/linux/dm-bufio.h b/include/linux/dm-bufio.h index e21480715255..15d9e15ca830 100644 --- a/include/linux/dm-bufio.h +++ b/include/linux/dm-bufio.h @@ -17,6 +17,11 @@ struct dm_bufio_client; struct dm_buffer; +/* + * Flags for dm_bufio_client_create + */ +#define DM_BUFIO_CLIENT_NO_SLEEP 0x1 + /* * Create a buffered IO cache on a given device */ -- cgit v1.2.3