Use spl_fstrans_mark instead of memalloc_noio_save

For earlier versions of the kernel with memalloc_noio_save, it only turns
off __GFP_IO but leaves __GFP_FS untouched during direct reclaim. This
would cause threads to direct reclaim into ZFS and cause deadlock.

Instead, we should stick to using spl_fstrans_mark. Since we would
explicitly turn off both __GFP_IO and __GFP_FS before allocation, it
will work on every version of the kernel.

This impacts kernel versions 3.9-3.17, see upstream kernel commit
torvalds/linux@934f307 for reference.

Signed-off-by: Chunwei Chen <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tim Chase <[email protected]>
Closes #515
Issue zfsonlinux/zfs#4111

1 files changed, 0 insertions, 25 deletions

diff --git a/module/spl/spl-vmem.c b/module/spl/spl-vmem.c
index bca27f263..e177988a7 100644
--- a/module/spl/spl-vmem.c
+++ b/module/spl/spl-vmem.c
@@ -97,31 +97,6 @@ spl_vmem_free(const void *buf, size_t size)
 }
 EXPORT_SYMBOL(spl_vmem_free);
 
-/*
- * Public vmalloc() interface designed to be safe to be called during I/O.
- */
-void *
-spl_vmalloc(unsigned long size, gfp_t lflags, pgprot_t prot)
-{
-#if defined(PF_MEMALLOC_NOIO)
-	void *ptr;
-	unsigned noio_flag = 0;
-
-	if (spl_fstrans_check())
-		noio_flag = memalloc_noio_save();
-
-	ptr =  __vmalloc(size, lflags, prot);
-
-	if (spl_fstrans_check())
-		memalloc_noio_restore(noio_flag);
-
-	return (ptr);
-#else
-	return (__vmalloc(size, lflags, prot));
-#endif
-}
-EXPORT_SYMBOL(spl_vmalloc);
-
 int
 spl_vmem_init(void)
 {