[GIT PULL] block fixes for 2.6.36-rc5

From: Jens Axboe
Date: Wed Sep 22 2010 - 03:49:29 EST


Hi Linus,

A small batch of fixes. Two important fixes, correcting a bug in the
unified request/bio command flags causing blk_rq_map_kern() to
flag writes incorrectly, and the oops in CFQ with cgroups and a usb key.
The small 3-patch series from Jan fixes a long standing regression
dating back to 2.6.32.

Please pull.

git://git.kernel.dk/linux-2.6-block.git for-linus

Benny Halevy (1):
block: fix blk_rq_map_kern bio direction flag

Dan Carpenter (1):
cciss: freeing uninitialized data on error path

Jan Kara (3):
bdi: Initialize noop_backing_dev_info properly
char: Mark /dev/zero and /dev/kmem as not capable of writeback
bdi: Fix warnings in __mark_inode_dirty for /dev/zero and friends

Vivek Goyal (1):
cfq-iosched: fix a kernel OOPs when usb key is inserted

block/blk-map.c | 2 +-
block/cfq-iosched.c | 16 +++++++++++++---
drivers/block/cciss.c | 2 +-
drivers/char/mem.c | 3 ++-
fs/char_dev.c | 4 +++-
fs/fs-writeback.c | 23 +++++++++++++++++++++--
mm/backing-dev.c | 2 ++
7 files changed, 43 insertions(+), 9 deletions(-)


diff --git a/block/blk-map.c b/block/blk-map.c
index c65d759..ade0a08 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -307,7 +307,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
return PTR_ERR(bio);

if (rq_data_dir(rq) == WRITE)
- bio->bi_rw |= (1 << REQ_WRITE);
+ bio->bi_rw |= REQ_WRITE;

if (do_copy)
rq->cmd_flags |= REQ_COPY_USER;
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f65c6f0..9eba291 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1019,10 +1019,20 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
*/
atomic_set(&cfqg->ref, 1);

- /* Add group onto cgroup list */
- sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
- cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
+ /*
+ * Add group onto cgroup list. It might happen that bdi->dev is
+ * not initiliazed yet. Initialize this new group without major
+ * and minor info and this info will be filled in once a new thread
+ * comes for IO. See code above.
+ */
+ if (bdi->dev) {
+ sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+ cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
MKDEV(major, minor));
+ } else
+ cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
+ 0);
+
cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);

/* Add group on cfqd list */
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 6124c2f..5e4fadc 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -4792,7 +4792,7 @@ static int __devinit cciss_init_one(struct pci_dev *pdev,
clean4:
kfree(h->cmd_pool_bits);
/* Free up sg elements */
- for (k = 0; k < h->nr_cmds; k++)
+ for (k-- ; k >= 0; k--)
kfree(h->scatter_list[k]);
kfree(h->scatter_list);
cciss_free_sg_chain_blocks(h->cmd_sg_list, h->nr_cmds);
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index a398ecd..1f528fa 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -788,10 +788,11 @@ static const struct file_operations zero_fops = {
/*
* capabilities for /dev/zero
* - permits private mappings, "copies" are taken of the source of zeros
+ * - no writeback happens
*/
static struct backing_dev_info zero_bdi = {
.name = "char/mem",
- .capabilities = BDI_CAP_MAP_COPY,
+ .capabilities = BDI_CAP_MAP_COPY | BDI_CAP_NO_ACCT_AND_WRITEBACK,
};

static const struct file_operations full_fops = {
diff --git a/fs/char_dev.c b/fs/char_dev.c
index f80a4f2..143d393 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -40,7 +40,9 @@ struct backing_dev_info directly_mappable_cdev_bdi = {
#endif
/* permit direct mmap, for read, write or exec */
BDI_CAP_MAP_DIRECT |
- BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP),
+ BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP |
+ /* no writeback happens */
+ BDI_CAP_NO_ACCT_AND_WRITEBACK),
};

static struct kobj_map *cdev_map;
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 81e086d..5581122 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -52,8 +52,6 @@ struct wb_writeback_work {
#define CREATE_TRACE_POINTS
#include <trace/events/writeback.h>

-#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info)
-
/*
* We don't actually have pdflush, but this one is exported though /proc...
*/
@@ -71,6 +69,27 @@ int writeback_in_progress(struct backing_dev_info *bdi)
return test_bit(BDI_writeback_running, &bdi->state);
}

+static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+ struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
+
+ /*
+ * For inodes on standard filesystems, we use superblock's bdi. For
+ * inodes on virtual filesystems, we want to use inode mapping's bdi
+ * because they can possibly point to something useful (think about
+ * block_dev filesystem).
+ */
+ if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) {
+ /* Some device inodes could play dirty tricks. Catch them... */
+ WARN(bdi != sb->s_bdi && bdi_cap_writeback_dirty(bdi),
+ "Dirtiable inode bdi %s != sb bdi %s\n",
+ bdi->name, sb->s_bdi->name);
+ return sb->s_bdi;
+ }
+ return bdi;
+}
+
static void bdi_queue_work(struct backing_dev_info *bdi,
struct wb_writeback_work *work)
{
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index c2bf86f..65d4204 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -30,6 +30,7 @@ EXPORT_SYMBOL_GPL(default_backing_dev_info);

struct backing_dev_info noop_backing_dev_info = {
.name = "noop",
+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
};
EXPORT_SYMBOL_GPL(noop_backing_dev_info);

@@ -243,6 +244,7 @@ static int __init default_bdi_init(void)
err = bdi_init(&default_backing_dev_info);
if (!err)
bdi_register(&default_backing_dev_info, NULL, "default");
+ err = bdi_init(&noop_backing_dev_info);

return err;
}
--
Jens Axboe

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