Eric Lee / smarc-ti-linux-kernel

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Commit 6f6b5d1ec56acdeab0503d2b823f6f88a0af493e

Authored by Kent Overstreet
Committed by Nicholas Bellinger
1 parent 4a4caa29f1
Exists in master and in 16 other branches dlt-processor-sdk-linux-03.00.00.04, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

percpu_ida: Make percpu_ida_alloc + callers accept task state bitmask 

This patch changes percpu_ida_alloc() + callers to accept task state
bitmask for prepare_to_wait() for code like target/iscsi that needs
it for interruptible sleep, that is provided in a subsequent patch.

It now expects TASK_UNINTERRUPTIBLE when the caller is able to sleep
waiting for a new tag, or TASK_RUNNING when the caller cannot sleep,
and is forced to return a negative value when no tags are available.

v2 changes:
  - Include blk-mq + tcm_fc + vhost/scsi + target/iscsi changes
  - Drop signal_pending_state() call
v3 changes:
  - Only call prepare_to_wait() + finish_wait() when != TASK_RUNNING
    (PeterZ)

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: <stable@vger.kernel.org> #3.12+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Showing 6 changed files with 23 additions and 14 deletions Side-by-side Diff

... ... @@ -36,7 +36,8 @@
36 36 {
37 37 int tag;
38 38  
39   - tag = percpu_ida_alloc(&tags->free_tags, gfp);
  39 + tag = percpu_ida_alloc(&tags->free_tags, (gfp & __GFP_WAIT) ?
  40 + TASK_UNINTERRUPTIBLE : TASK_RUNNING);
40 41 if (tag < 0)
41 42 return BLK_MQ_TAG_FAIL;
42 43 return tag + tags->nr_reserved_tags;
... ... @@ -52,7 +53,8 @@
52 53 return BLK_MQ_TAG_FAIL;
53 54 }
54 55  
55   - tag = percpu_ida_alloc(&tags->reserved_tags, gfp);
  56 + tag = percpu_ida_alloc(&tags->reserved_tags, (gfp & __GFP_WAIT) ?
  57 + TASK_UNINTERRUPTIBLE : TASK_RUNNING);
56 58 if (tag < 0)
57 59 return BLK_MQ_TAG_FAIL;
58 60 return tag;
drivers/target/iscsi/iscsi_target_util.c
Diff comments   View file @ 6f6b5d1
... ... @@ -156,9 +156,13 @@
156 156 {
157 157 struct iscsi_cmd *cmd;
158 158 struct se_session *se_sess = conn->sess->se_sess;
159   - int size, tag;
  159 + int size, tag, state = (gfp_mask & __GFP_WAIT) ? TASK_UNINTERRUPTIBLE :
  160 + TASK_RUNNING;
160 161  
161   - tag = percpu_ida_alloc(&se_sess->sess_tag_pool, gfp_mask);
  162 + tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state);
  163 + if (tag < 0)
  164 + return NULL;
  165 +
162 166 size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size;
163 167 cmd = (struct iscsi_cmd *)(se_sess->sess_cmd_map + (tag * size));
164 168 memset(cmd, 0, size);
drivers/target/tcm_fc/tfc_cmd.c
Diff comments   View file @ 6f6b5d1
... ... @@ -438,7 +438,7 @@
438 438 struct se_session *se_sess = sess->se_sess;
439 439 int tag;
440 440  
441   - tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_ATOMIC);
  441 + tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
442 442 if (tag < 0)
443 443 goto busy;
444 444  
drivers/vhost/scsi.c
Diff comments   View file @ 6f6b5d1
... ... @@ -728,7 +728,7 @@
728 728 }
729 729 se_sess = tv_nexus->tvn_se_sess;
730 730  
731   - tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_ATOMIC);
  731 + tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);
732 732 if (tag < 0) {
733 733 pr_err("Unable to obtain tag for tcm_vhost_cmd\n");
734 734 return ERR_PTR(-ENOMEM);
include/linux/percpu_ida.h
Diff comments   View file @ 6f6b5d1
... ... @@ -4,6 +4,7 @@
4 4 #include <linux/types.h>
5 5 #include <linux/bitops.h>
6 6 #include <linux/init.h>
  7 +#include <linux/sched.h>
7 8 #include <linux/spinlock_types.h>
8 9 #include <linux/wait.h>
9 10 #include <linux/cpumask.h>
... ... @@ -61,7 +62,7 @@
61 62 /* Max size of percpu freelist, */
62 63 #define IDA_DEFAULT_PCPU_SIZE ((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2)
63 64  
64   -int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp);
  65 +int percpu_ida_alloc(struct percpu_ida *pool, int state);
65 66 void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
66 67  
67 68 void percpu_ida_destroy(struct percpu_ida *pool);
... ... @@ -132,22 +132,22 @@
132 132 /**
133 133 * percpu_ida_alloc - allocate a tag
134 134 * @pool: pool to allocate from
135   - * @gfp: gfp flags
  135 + * @state: task state for prepare_to_wait
136 136 *
137 137 * Returns a tag - an integer in the range [0..nr_tags) (passed to
138 138 * tag_pool_init()), or otherwise -ENOSPC on allocation failure.
139 139 *
140 140 * Safe to be called from interrupt context (assuming it isn't passed
141   - * __GFP_WAIT, of course).
  141 + * TASK_UNINTERRUPTIBLE, of course).
142 142 *
143 143 * @gfp indicates whether or not to wait until a free id is available (it's not
144 144 * used for internal memory allocations); thus if passed __GFP_WAIT we may sleep
145 145 * however long it takes until another thread frees an id (same semantics as a
146 146 * mempool).
147 147 *
148   - * Will not fail if passed __GFP_WAIT.
  148 + * Will not fail if passed TASK_UNINTERRUPTIBLE.
149 149 */
150   -int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp)
  150 +int percpu_ida_alloc(struct percpu_ida *pool, int state)
151 151 {
152 152 DEFINE_WAIT(wait);
153 153 struct percpu_ida_cpu *tags;
... ... @@ -174,7 +174,8 @@
174 174 *
175 175 * global lock held and irqs disabled, don't need percpu lock
176 176 */
177   - prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
  177 + if (state != TASK_RUNNING)
  178 + prepare_to_wait(&pool->wait, &wait, state);
178 179  
179 180 if (!tags->nr_free)
180 181 alloc_global_tags(pool, tags);
... ... @@ -191,7 +192,7 @@
191 192 spin_unlock(&pool->lock);
192 193 local_irq_restore(flags);
193 194  
194   - if (tag >= 0 || !(gfp & __GFP_WAIT))
  195 + if (tag >= 0 || state == TASK_RUNNING)
195 196 break;
196 197  
197 198 schedule();
198 199  
... ... @@ -199,8 +200,9 @@
199 200 local_irq_save(flags);
200 201 tags = this_cpu_ptr(pool->tag_cpu);
201 202 }
  203 + if (state != TASK_RUNNING)
  204 + finish_wait(&pool->wait, &wait);
202 205  
203   - finish_wait(&pool->wait, &wait);
204 206 return tag;
205 207 }
206 208 EXPORT_SYMBOL_GPL(percpu_ida_alloc);