UBI: allocate memory with GFP_NOFS

Use GFP_NOFS flag when allocating memory on I/O path, because otherwise
we may deadlock the filesystem which works on top of us. We observed
the deadlocks with UBIFS. Example:

VFS->FS lock a lock->UBI->kmalloc()->VFS writeback->FS locks the same
lock again.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

6 files changed, 21 insertions, 19 deletions

diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index 7c5e29eaf118..89193104c6c8 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -157,7 +157,7 @@ static struct ltree_entry *ltree_add_entry(struct ubi_device *ubi, int vol_id,
 {
         struct ltree_entry *le, *le1, *le_free;
 
-        le = kmem_cache_alloc(ltree_slab, GFP_KERNEL);
+        le = kmem_cache_alloc(ltree_slab, GFP_NOFS);
         if (!le)
                 return ERR_PTR(-ENOMEM);
 
@@ -397,7 +397,7 @@ int ubi_eba_read_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
 
 retry:
         if (check) {
-                vid_hdr = ubi_zalloc_vid_hdr(ubi);
+                vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
                 if (!vid_hdr) {
                         err = -ENOMEM;
                         goto out_unlock;
@@ -497,7 +497,7 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
         struct ubi_vid_hdr *vid_hdr;
         unsigned char *new_buf;
 
-        vid_hdr = ubi_zalloc_vid_hdr(ubi);
+        vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
         if (!vid_hdr) {
                 return -ENOMEM;
         }
@@ -627,7 +627,7 @@ int ubi_eba_write_leb(struct ubi_device *ubi, int vol_id, int lnum,
          * The logical eraseblock is not mapped. We have to get a free physical
          * eraseblock and write the volume identifier header there first.
          */
-        vid_hdr = ubi_zalloc_vid_hdr(ubi);
+        vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
         if (!vid_hdr) {
                 leb_write_unlock(ubi, vol_id, lnum);
                 return -ENOMEM;
@@ -738,7 +738,7 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, int vol_id, int lnum,
         else
                 ubi_assert(len % ubi->min_io_size == 0);
 
-        vid_hdr = ubi_zalloc_vid_hdr(ubi);
+        vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
         if (!vid_hdr)
                 return -ENOMEM;
 
@@ -844,7 +844,7 @@ int ubi_eba_atomic_leb_change(struct ubi_device *ubi, int vol_id, int lnum,
         if (ubi->ro_mode)
                 return -EROFS;
 
-        vid_hdr = ubi_zalloc_vid_hdr(ubi);
+        vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
         if (!vid_hdr)
                 return -ENOMEM;
 
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 928476394d55..ba5bc4a5379e 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -1099,7 +1099,7 @@ static int paranoid_check_peb_ec_hdr(const struct ubi_device *ubi, int pnum)
         uint32_t crc, hdr_crc;
         struct ubi_ec_hdr *ec_hdr;
 
-        ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+        ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
         if (!ec_hdr)
                 return -ENOMEM;
 
@@ -1179,7 +1179,7 @@ static int paranoid_check_peb_vid_hdr(const struct ubi_device *ubi, int pnum)
         struct ubi_vid_hdr *vid_hdr;
         void *p;
 
-        vid_hdr = ubi_zalloc_vid_hdr(ubi);
+        vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
         if (!vid_hdr)
                 return -ENOMEM;
 
diff --git a/drivers/mtd/ubi/scan.c b/drivers/mtd/ubi/scan.c
index 18c347b24e27..1c1401d6958b 100644
--- a/drivers/mtd/ubi/scan.c
+++ b/drivers/mtd/ubi/scan.c
@@ -323,7 +323,7 @@ static int compare_lebs(const struct ubi_device *ubi,
         } else {
                 pnum = seb->pnum;
 
-                vh = ubi_zalloc_vid_hdr(ubi);
+                vh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
                 if (!vh)
                         return -ENOMEM;
 
@@ -948,7 +948,7 @@ struct ubi_scan_info *ubi_scan(struct ubi_device *ubi)
         if (!ech)
                 goto out_si;
 
-        vidh = ubi_zalloc_vid_hdr(ubi);
+        vidh = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
         if (!vidh)
                 goto out_ech;
 
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index 5959f91be240..329663188772 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -439,16 +439,18 @@ int ubi_io_write_vid_hdr(const struct ubi_device *ubi, int pnum,
 /**
  * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
  * @ubi: UBI device description object
+ * @gfp_flags: GFP flags to allocate with
  *
  * This function returns a pointer to the newly allocated and zero-filled
  * volume identifier header object in case of success and %NULL in case of
  * failure.
  */
-static inline struct ubi_vid_hdr *ubi_zalloc_vid_hdr(const struct ubi_device *ubi)
+static inline struct ubi_vid_hdr *
+ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
 {
         void *vid_hdr;
 
-        vid_hdr = kzalloc(ubi->vid_hdr_alsize, GFP_KERNEL);
+        vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
         if (!vid_hdr)
                 return NULL;
 
diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
index bc5df50813d6..b0a1e8426456 100644
--- a/drivers/mtd/ubi/vtbl.c
+++ b/drivers/mtd/ubi/vtbl.c
@@ -264,7 +264,7 @@ static int create_vtbl(const struct ubi_device *ubi, struct ubi_scan_info *si,
 
         ubi_msg("create volume table (copy #%d)", copy + 1);
 
-        vid_hdr = ubi_zalloc_vid_hdr(ubi);
+        vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_KERNEL);
         if (!vid_hdr)
                 return -ENOMEM;
 
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index 12b25e5b7b81..248ff9e477e7 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -508,7 +508,7 @@ int ubi_wl_get_peb(struct ubi_device *ubi, int dtype)
         ubi_assert(dtype == UBI_LONGTERM || dtype == UBI_SHORTTERM ||
                    dtype == UBI_UNKNOWN);
 
-        pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_KERNEL);
+        pe = kmalloc(sizeof(struct ubi_wl_prot_entry), GFP_NOFS);
         if (!pe)
                 return -ENOMEM;
 
@@ -645,7 +645,7 @@ static int sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e, int tortur
         if (err > 0)
                 return -EINVAL;
 
-        ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+        ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
         if (!ec_hdr)
                 return -ENOMEM;
 
@@ -768,7 +768,7 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
         dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
                e->pnum, e->ec, torture);
 
-        wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_KERNEL);
+        wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
         if (!wl_wrk)
                 return -ENOMEM;
 
@@ -802,7 +802,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
         if (cancel)
                 return 0;
 
-        vid_hdr = ubi_zalloc_vid_hdr(ubi);
+        vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
         if (!vid_hdr)
                 return -ENOMEM;
 
@@ -1028,7 +1028,7 @@ static int ensure_wear_leveling(struct ubi_device *ubi)
         ubi->wl_scheduled = 1;
         spin_unlock(&ubi->wl_lock);
 
-        wrk = kmalloc(sizeof(struct ubi_work), GFP_KERNEL);
+        wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
         if (!wrk) {
                 err = -ENOMEM;
                 goto out_cancel;
@@ -1631,7 +1631,7 @@ static int paranoid_check_ec(const struct ubi_device *ubi, int pnum, int ec)
         long long read_ec;
         struct ubi_ec_hdr *ec_hdr;
 
-        ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_KERNEL);
+        ec_hdr = kzalloc(ubi->ec_hdr_alsize, GFP_NOFS);
         if (!ec_hdr)
                 return -ENOMEM;