[SCSI] st: fix mdata->page_order handling
authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Thu, 26 Nov 2009 00:24:13 +0000 (09:24 +0900)
committerJames Bottomley <James.Bottomley@suse.de>
Thu, 10 Dec 2009 14:54:13 +0000 (08:54 -0600)
commitc982c368bb90adbd312faa05d0cfd842e9ab45a7
treee5620557e3972c130e4b4b652d036a378d0f977b
parent78b9fb6d38b1caf1c11cba5b10bb859e3cce071f
[SCSI] st: fix mdata->page_order handling

dio transfer always resets mdata->page_order to zero. It breaks
high-order pages previously allocated for non-dio transfer.

This patches adds reserved_page_order to st_buffer structure to save
page order for non-dio transfer.

http://bugzilla.kernel.org/show_bug.cgi?id=14563

When enlarge_buffer() allocates 524288 from 0, st uses six-order page
allocation. So mdata->page_order is 6 and frp_seg is 2.

After that, if st uses dio, sgl_map_user_pages() sets
mdata->page_order to 0 for st_do_scsi(). After that, when we call
normalize_buffer(), it frees only free frp_seg * PAGE_SIZE (2 * 4096)
though we should free frp_seg * PAGE_SIZE << 6 (2 * 4096 << 6). So we
see buffer_size is set to 516096 (524288 - 8192).

Reported-by: Joachim Breuer <linux-kernel@jmbreuer.net>
Tested-by: Joachim Breuer <linux-kernel@jmbreuer.net>
Acked-by: Kai Makisara <kai.makisara@kolumbus.fi>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: stable@kernel.org
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
drivers/scsi/st.c
drivers/scsi/st.h