summaryrefslogtreecommitdiffstats
path: root/drivers/md/dm-round-robin.c
Commit message (Collapse)AuthorAgeFilesLines
* dm round robin: use percpu 'repeat_count' and 'current_path'Mike Snitzer2016-02-221-12/+48
| | | | | | | | | | | | | | Now that dm-mpath core is lockless in the per-IO fast path it is critical, for performance, to have the .select_path hook (rr_select_path) also be as lockless as possible. The new percpu members of 'struct selector' allow for lockless support of 'repeat_count' governed repeat use of a previously selected path. If a path fails while it is 'current_path' the worst case is concurrent IO might be mapped to the failed path until the .fail_path hook (rr_fail_path) is called. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm path selector: remove 'repeat_count' return from .select_path hookMike Snitzer2016-02-221-3/+1
| | | | | | | If a path selector has any use for a repeat_count it should be handled locally and not depend on the dm-mpath core to be concerned with it. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm mpath: push path selector locking down to path selectorsMike Snitzer2016-02-221-5/+19
| | | | | | | | Proper locking of the lists used by the path selectors should be handled within the selectors (relying on dm-mpath.c code's use of the m->lock spinlock was reckless). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm mpath: remove repeat_count support from multipath coreMike Snitzer2016-02-221-3/+8
| | | | | | | | | | | | | | Preparation for making __multipath_map() avoid taking the m->lock spinlock -- in favor of using RCU locking. repeat_count was primarily for bio-based DM multipath's benefit. There is really no need for it anymore now that DM multipath is request-based. As such, repeat_count > 1 is no longer honored and a warning is displayed if the user attempts to use a value > 1. This is a temporary change for the round-robin path-selector (as a later commit will restore its support for repeat_count > 1). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
* dm: reject trailing characters in sccanf inputMikulas Patocka2012-03-281-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | Device mapper uses sscanf to convert arguments to numbers. The problem is that the way we use it ignores additional unmatched characters in the scanned string. For example, this `if (sscanf(string, "%d", &number) == 1)' will match a number, but also it will match number with some garbage appended, like "123abc". As a result, device mapper accepts garbage after some numbers. For example the command `dmsetup create vg1-new --table "0 16384 linear 254:1bla 34816bla"' will pass without an error. This patch fixes all sscanf uses in device mapper. It appends "%c" with a pointer to a dummy character variable to every sscanf statement. The construct `if (sscanf(string, "%d%c", &number, &dummy) == 1)' succeeds only if string is a null-terminated number (optionally preceded by some whitespace characters). If there is some character appended after the number, sscanf matches "%c", writes the character to the dummy variable and returns 2. We check the return value for 1 and consequently reject numbers with some garbage appended. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* md: Add module.h to all files using it implicitlyPaul Gortmaker2011-10-311-0/+1
| | | | | | | | A pending cleanup will mean that module.h won't be implicitly everywhere anymore. Make sure the modular drivers in md dir are actually calling out for <module.h> explicitly in advance. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* dm mpath: add start_io and nr_bytes to path selectorsKiyoshi Ueda2009-06-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes two additions to the dm path selector interface for dynamic load balancers: o a new hook, start_io() o a new parameter 'nr_bytes' to select_path()/start_io()/end_io() to pass the size of the I/O start_io() is called when a target driver actually submits I/O to the selected path. Path selectors can use it to start accounting of the I/O. (e.g. counting the number of in-flight I/Os.) The start_io hook is based on the patch posted by Stefan Bader: https://www.redhat.com/archives/dm-devel/2005-October/msg00050.html nr_bytes, the size of the I/O, is so path selectors can take the size of the I/O into account when deciding which path to use. dm-service-time uses it to estimate service time, for example. (Added the nr_bytes member to dm_mpath_io instead of using existing details.bi_size, since request-based dm patch deletes it.) Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: remove dm header from targetsMikulas Patocka2008-10-211-1/+2
| | | | | | | | Change #include "dm.h" to #include <linux/device-mapper.h> in all targets. Targets should not need direct access to internal DM structures. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
* dm: remove duplicate module name from error msgsAlasdair G Kergon2007-07-121-1/+1
| | | | | | | | Remove explicit module name from messages as the macro now includes it automatically. Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] struct path: rename DM's struct pathJosef "Jeff" Sipek2006-12-081-6/+6
| | | | | | | | | | | | Rename DM's struct path to struct dm_path to prevent name collision between it and struct path from fs/namei.c. Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Acked-by: Alasdair G Kergon <agk@redhat.com> Cc: <reiserfs-dev@namesys.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] dm: multipath: fix rr_add_path orderJonathan E Brassow2006-11-081-1/+1
| | | | | | | | | | | | | When adding paths to the round-robin path selector, their order gets inverted, which is not desirable. Fix by replacing list_add() with list_add_tail(). Signed-off-by: Jonathan E Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Cc: <dm-devel@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] dm: improve error message consistencyAlasdair G Kergon2006-06-261-2/+4
| | | | | | | | | Tidy device-mapper error messages to include context information automatically. Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+214
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
OpenPOWER on IntegriCloud