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authorLinus Torvalds <torvalds@linux-foundation.org>2010-10-22 17:00:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-22 17:00:32 -0700
commite9dd2b6837e26fe202708cce5ea4bb4ee3e3482e (patch)
treef42fd892495bfc4cbb740d06b016d267c9c42d00 /init
parent4f3a29dadaf999a273f1e7fe2476595d0283eef3 (diff)
parentb4627321e18582dcbdeb45d77df29d3177107c65 (diff)
downloadlinux-2.6.38-lt-ux500-e9dd2b6837e26fe202708cce5ea4bb4ee3e3482e.tar.gz
Merge branch 'for-2.6.37/core' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.37/core' of git://git.kernel.dk/linux-2.6-block: (39 commits) cfq-iosched: Fix a gcc 4.5 warning and put some comments block: Turn bvec_k{un,}map_irq() into static inline functions block: fix accounting bug on cross partition merges block: Make the integrity mapped property a bio flag block: Fix double free in blk_integrity_unregister block: Ensure physical block size is unsigned int blkio-throttle: Fix possible multiplication overflow in iops calculations blkio-throttle: limit max iops value to UINT_MAX blkio-throttle: There is no need to convert jiffies to milli seconds blkio-throttle: Fix link failure failure on i386 blkio: Recalculate the throttled bio dispatch time upon throttle limit change blkio: Add root group to td->tg_list blkio: deletion of a cgroup was causes oops blkio: Do not export throttle files if CONFIG_BLK_DEV_THROTTLING=n block: set the bounce_pfn to the actual DMA limit rather than to max memory block: revert bad fix for memory hotplug causing bounces Fix compile error in blk-exec.c for !CONFIG_DETECT_HUNG_TASK block: set the bounce_pfn to the actual DMA limit rather than to max memory block: Prevent hang_check firing during long I/O cfq: improve fsync performance for small files ... Fix up trivial conflicts due to __rcu sparse annotation in include/linux/genhd.h
Diffstat (limited to 'init')
-rw-r--r--init/Kconfig9
-rw-r--r--init/do_mounts.c70
2 files changed, 76 insertions, 3 deletions
diff --git a/init/Kconfig b/init/Kconfig
index be85a0ab1b8..bd125a79537 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -661,11 +661,14 @@ config BLK_CGROUP
Currently, CFQ IO scheduler uses it to recognize task groups and
control disk bandwidth allocation (proportional time slice allocation)
- to such task groups.
+ to such task groups. It is also used by bio throttling logic in
+ block layer to implement upper limit in IO rates on a device.
This option only enables generic Block IO controller infrastructure.
- One needs to also enable actual IO controlling logic in CFQ for it
- to take effect. (CONFIG_CFQ_GROUP_IOSCHED=y).
+ One needs to also enable actual IO controlling logic/policy. For
+ enabling proportional weight division of disk bandwidth in CFQ seti
+ CONFIG_CFQ_GROUP_IOSCHED=y and for enabling throttling policy set
+ CONFIG_BLK_THROTTLE=y.
See Documentation/cgroups/blkio-controller.txt for more information.
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 02e3ca4fc52..42db0551c3a 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -58,6 +58,62 @@ static int __init readwrite(char *str)
__setup("ro", readonly);
__setup("rw", readwrite);
+#ifdef CONFIG_BLOCK
+/**
+ * match_dev_by_uuid - callback for finding a partition using its uuid
+ * @dev: device passed in by the caller
+ * @data: opaque pointer to a 36 byte char array with a UUID
+ *
+ * Returns 1 if the device matches, and 0 otherwise.
+ */
+static int match_dev_by_uuid(struct device *dev, void *data)
+{
+ u8 *uuid = data;
+ struct hd_struct *part = dev_to_part(dev);
+
+ if (!part->info)
+ goto no_match;
+
+ if (memcmp(uuid, part->info->uuid, sizeof(part->info->uuid)))
+ goto no_match;
+
+ return 1;
+no_match:
+ return 0;
+}
+
+
+/**
+ * devt_from_partuuid - looks up the dev_t of a partition by its UUID
+ * @uuid: 36 byte char array containing a hex ascii UUID
+ *
+ * The function will return the first partition which contains a matching
+ * UUID value in its partition_meta_info struct. This does not search
+ * by filesystem UUIDs.
+ *
+ * Returns the matching dev_t on success or 0 on failure.
+ */
+static dev_t __init devt_from_partuuid(char *uuid_str)
+{
+ dev_t res = 0;
+ struct device *dev = NULL;
+ u8 uuid[16];
+
+ /* Pack the requested UUID in the expected format. */
+ part_pack_uuid(uuid_str, uuid);
+
+ dev = class_find_device(&block_class, NULL, uuid, &match_dev_by_uuid);
+ if (!dev)
+ goto done;
+
+ res = dev->devt;
+ put_device(dev);
+
+done:
+ return res;
+}
+#endif
+
/*
* Convert a name into device number. We accept the following variants:
*
@@ -68,6 +124,8 @@ __setup("rw", readwrite);
* of partition - device number of disk plus the partition number
* 5) /dev/<disk_name>p<decimal> - same as the above, that form is
* used when disk name of partitioned disk ends on a digit.
+ * 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
+ * unique id of a partition if the partition table provides it.
*
* If name doesn't have fall into the categories above, we return (0,0).
* block_class is used to check if something is a disk name. If the disk
@@ -82,6 +140,18 @@ dev_t name_to_dev_t(char *name)
dev_t res = 0;
int part;
+#ifdef CONFIG_BLOCK
+ if (strncmp(name, "PARTUUID=", 9) == 0) {
+ name += 9;
+ if (strlen(name) != 36)
+ goto fail;
+ res = devt_from_partuuid(name);
+ if (!res)
+ goto fail;
+ goto done;
+ }
+#endif
+
if (strncmp(name, "/dev/", 5) != 0) {
unsigned maj, min;