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ldesrochesVinod Koul
ldesroches
authored and
Vinod Koul
committed
dmaengine: at_xdmac: lock fixes
Using _bh variant for spin locks causes this kind of warning: Starting logging: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 3 at /ssd_drive/linux/kernel/softirq.c:151 __local_bh_enable_ip+0xe8/0xf4() Modules linked in: CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.1.0-rc2+ torvalds#94 Hardware name: Atmel SAMA5 [<c0013c04>] (unwind_backtrace) from [<c00118a4>] (show_stack+0x10/0x14) [<c00118a4>] (show_stack) from [<c001bbcc>] (warn_slowpath_common+0x80/0xac) [<c001bbcc>] (warn_slowpath_common) from [<c001bc14>] (warn_slowpath_null+0x1c/0x24) [<c001bc14>] (warn_slowpath_null) from [<c001e28c>] (__local_bh_enable_ip+0xe8/0xf4) [<c001e28c>] (__local_bh_enable_ip) from [<c01fdbd0>] (at_xdmac_device_terminate_all+0xf4/0x100) [<c01fdbd0>] (at_xdmac_device_terminate_all) from [<c02221a4>] (atmel_complete_tx_dma+0x34/0xf4) [<c02221a4>] (atmel_complete_tx_dma) from [<c01fe4ac>] (at_xdmac_tasklet+0x14c/0x1ac) [<c01fe4ac>] (at_xdmac_tasklet) from [<c001de58>] (tasklet_action+0x68/0xb4) [<c001de58>] (tasklet_action) from [<c001dfdc>] (__do_softirq+0xfc/0x238) [<c001dfdc>] (__do_softirq) from [<c001e140>] (run_ksoftirqd+0x28/0x34) [<c001e140>] (run_ksoftirqd) from [<c0033a3c>] (smpboot_thread_fn+0x138/0x18c) [<c0033a3c>] (smpboot_thread_fn) from [<c0030e7c>] (kthread+0xdc/0xf0) [<c0030e7c>] (kthread) from [<c000f480>] (ret_from_fork+0x14/0x34) ---[ end trace b57b14a99c1d8812 ]--- It comes from the fact that devices can called some code from the DMA controller with irq disabled. _bh variant is not intended to be used in this case since it can enable irqs. Switch to irqsave/irqrestore variant to avoid this situation. Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com> Cc: stable@vger.kernel.org # 4.0 and later Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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‎drivers/dma/at_xdmac.c‎

Lines changed: 43 additions & 32 deletions
Original file line numberDiff line numberDiff line change
@@ -415,8 +415,9 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx)
415415
struct at_xdmac_desc *desc = txd_to_at_desc(tx);
416416
struct at_xdmac_chan *atchan = to_at_xdmac_chan(tx->chan);
417417
dma_cookie_t cookie;
418+
unsigned long irqflags;
418419

419-
spin_lock_bh(&atchan->lock);
420+
spin_lock_irqsave(&atchan->lock, irqflags);
420421
cookie = dma_cookie_assign(tx);
421422

422423
dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n",
@@ -425,7 +426,7 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx)
425426
if (list_is_singular(&atchan->xfers_list))
426427
at_xdmac_start_xfer(atchan, desc);
427428

428-
spin_unlock_bh(&atchan->lock);
429+
spin_unlock_irqrestore(&atchan->lock, irqflags);
429430
return cookie;
430431
}
431432

@@ -563,6 +564,8 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
563564
struct scatterlist *sg;
564565
int i;
565566
unsigned int xfer_size = 0;
567+
unsigned long irqflags;
568+
struct dma_async_tx_descriptor *ret = NULL;
566569

567570
if (!sgl)
568571
return NULL;
@@ -578,7 +581,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
578581
flags);
579582

580583
/* Protect dma_sconfig field that can be modified by set_slave_conf. */
581-
spin_lock_bh(&atchan->lock);
584+
spin_lock_irqsave(&atchan->lock, irqflags);
582585

583586
/* Prepare descriptors. */
584587
for_each_sg(sgl, sg, sg_len, i) {
@@ -589,8 +592,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
589592
mem = sg_dma_address(sg);
590593
if (unlikely(!len)) {
591594
dev_err(chan2dev(chan), "sg data length is zero\n");
592-
spin_unlock_bh(&atchan->lock);
593-
return NULL;
595+
goto spin_unlock;
594596
}
595597
dev_dbg(chan2dev(chan), "%s: * sg%d len=%u, mem=0x%08x\n",
596598
__func__, i, len, mem);
@@ -600,8 +602,7 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
600602
dev_err(chan2dev(chan), "can't get descriptor\n");
601603
if (first)
602604
list_splice_init(&first->descs_list, &atchan->free_descs_list);
603-
spin_unlock_bh(&atchan->lock);
604-
return NULL;
605+
goto spin_unlock;
605606
}
606607

607608
/* Linked list descriptor setup. */
@@ -645,13 +646,15 @@ at_xdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
645646
xfer_size += len;
646647
}
647648

648-
spin_unlock_bh(&atchan->lock);
649649

650650
first->tx_dma_desc.flags = flags;
651651
first->xfer_size = xfer_size;
652652
first->direction = direction;
653+
ret = &first->tx_dma_desc;
653654

654-
return &first->tx_dma_desc;
655+
spin_unlock:
656+
spin_unlock_irqrestore(&atchan->lock, irqflags);
657+
return ret;
655658
}
656659

657660
static struct dma_async_tx_descriptor *
@@ -664,6 +667,7 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
664667
struct at_xdmac_desc *first = NULL, *prev = NULL;
665668
unsigned int periods = buf_len / period_len;
666669
int i;
670+
unsigned long irqflags;
667671

668672
dev_dbg(chan2dev(chan), "%s: buf_addr=%pad, buf_len=%zd, period_len=%zd, dir=%s, flags=0x%lx\n",
669673
__func__, &buf_addr, buf_len, period_len,
@@ -682,16 +686,16 @@ at_xdmac_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr,
682686
for (i = 0; i < periods; i++) {
683687
struct at_xdmac_desc *desc = NULL;
684688

685-
spin_lock_bh(&atchan->lock);
689+
spin_lock_irqsave(&atchan->lock, irqflags);
686690
desc = at_xdmac_get_desc(atchan);
687691
if (!desc) {
688692
dev_err(chan2dev(chan), "can't get descriptor\n");
689693
if (first)
690694
list_splice_init(&first->descs_list, &atchan->free_descs_list);
691-
spin_unlock_bh(&atchan->lock);
695+
spin_unlock_irqrestore(&atchan->lock, irqflags);
692696
return NULL;
693697
}
694-
spin_unlock_bh(&atchan->lock);
698+
spin_unlock_irqrestore(&atchan->lock, irqflags);
695699
dev_dbg(chan2dev(chan),
696700
"%s: desc=0x%p, tx_dma_desc.phys=%pad\n",
697701
__func__, desc, &desc->tx_dma_desc.phys);
@@ -766,6 +770,7 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
766770
| AT_XDMAC_CC_SIF(0)
767771
| AT_XDMAC_CC_MBSIZE_SIXTEEN
768772
| AT_XDMAC_CC_TYPE_MEM_TRAN;
773+
unsigned long irqflags;
769774

770775
dev_dbg(chan2dev(chan), "%s: src=%pad, dest=%pad, len=%zd, flags=0x%lx\n",
771776
__func__, &src, &dest, len, flags);
@@ -798,9 +803,9 @@ at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
798803

799804
dev_dbg(chan2dev(chan), "%s: remaining_size=%zu\n", __func__, remaining_size);
800805

801-
spin_lock_bh(&atchan->lock);
806+
spin_lock_irqsave(&atchan->lock, irqflags);
802807
desc = at_xdmac_get_desc(atchan);
803-
spin_unlock_bh(&atchan->lock);
808+
spin_unlock_irqrestore(&atchan->lock, irqflags);
804809
if (!desc) {
805810
dev_err(chan2dev(chan), "can't get descriptor\n");
806811
if (first)
@@ -886,6 +891,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
886891
int residue;
887892
u32 cur_nda, mask, value;
888893
u8 dwidth = 0;
894+
unsigned long flags;
889895

890896
ret = dma_cookie_status(chan, cookie, txstate);
891897
if (ret == DMA_COMPLETE)
@@ -894,7 +900,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
894900
if (!txstate)
895901
return ret;
896902

897-
spin_lock_bh(&atchan->lock);
903+
spin_lock_irqsave(&atchan->lock, flags);
898904

899905
desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, xfer_node);
900906

@@ -904,8 +910,7 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
904910
*/
905911
if (!desc->active_xfer) {
906912
dma_set_residue(txstate, desc->xfer_size);
907-
spin_unlock_bh(&atchan->lock);
908-
return ret;
913+
goto spin_unlock;
909914
}
910915

911916
residue = desc->xfer_size;
@@ -936,14 +941,14 @@ at_xdmac_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
936941
}
937942
residue += at_xdmac_chan_read(atchan, AT_XDMAC_CUBC) << dwidth;
938943

939-
spin_unlock_bh(&atchan->lock);
940-
941944
dma_set_residue(txstate, residue);
942945

943946
dev_dbg(chan2dev(chan),
944947
"%s: desc=0x%p, tx_dma_desc.phys=%pad, tx_status=%d, cookie=%d, residue=%d\n",
945948
__func__, desc, &desc->tx_dma_desc.phys, ret, cookie, residue);
946949

950+
spin_unlock:
951+
spin_unlock_irqrestore(&atchan->lock, flags);
947952
return ret;
948953
}
949954

@@ -964,8 +969,9 @@ static void at_xdmac_remove_xfer(struct at_xdmac_chan *atchan,
964969
static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
965970
{
966971
struct at_xdmac_desc *desc;
972+
unsigned long flags;
967973

968-
spin_lock_bh(&atchan->lock);
974+
spin_lock_irqsave(&atchan->lock, flags);
969975

970976
/*
971977
* If channel is enabled, do nothing, advance_work will be triggered
@@ -980,7 +986,7 @@ static void at_xdmac_advance_work(struct at_xdmac_chan *atchan)
980986
at_xdmac_start_xfer(atchan, desc);
981987
}
982988

983-
spin_unlock_bh(&atchan->lock);
989+
spin_unlock_irqrestore(&atchan->lock, flags);
984990
}
985991

986992
static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
@@ -1116,12 +1122,13 @@ static int at_xdmac_device_config(struct dma_chan *chan,
11161122
{
11171123
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
11181124
int ret;
1125+
unsigned long flags;
11191126

11201127
dev_dbg(chan2dev(chan), "%s\n", __func__);
11211128

1122-
spin_lock_bh(&atchan->lock);
1129+
spin_lock_irqsave(&atchan->lock, flags);
11231130
ret = at_xdmac_set_slave_config(chan, config);
1124-
spin_unlock_bh(&atchan->lock);
1131+
spin_unlock_irqrestore(&atchan->lock, flags);
11251132

11261133
return ret;
11271134
}
@@ -1130,18 +1137,19 @@ static int at_xdmac_device_pause(struct dma_chan *chan)
11301137
{
11311138
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
11321139
struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device);
1140+
unsigned long flags;
11331141

11341142
dev_dbg(chan2dev(chan), "%s\n", __func__);
11351143

11361144
if (test_and_set_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status))
11371145
return 0;
11381146

1139-
spin_lock_bh(&atchan->lock);
1147+
spin_lock_irqsave(&atchan->lock, flags);
11401148
at_xdmac_write(atxdmac, AT_XDMAC_GRWS, atchan->mask);
11411149
while (at_xdmac_chan_read(atchan, AT_XDMAC_CC)
11421150
& (AT_XDMAC_CC_WRIP | AT_XDMAC_CC_RDIP))
11431151
cpu_relax();
1144-
spin_unlock_bh(&atchan->lock);
1152+
spin_unlock_irqrestore(&atchan->lock, flags);
11451153

11461154
return 0;
11471155
}
@@ -1150,18 +1158,19 @@ static int at_xdmac_device_resume(struct dma_chan *chan)
11501158
{
11511159
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
11521160
struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device);
1161+
unsigned long flags;
11531162

11541163
dev_dbg(chan2dev(chan), "%s\n", __func__);
11551164

1156-
spin_lock_bh(&atchan->lock);
1165+
spin_lock_irqsave(&atchan->lock, flags);
11571166
if (!at_xdmac_chan_is_paused(atchan)) {
1158-
spin_unlock_bh(&atchan->lock);
1167+
spin_unlock_irqrestore(&atchan->lock, flags);
11591168
return 0;
11601169
}
11611170

11621171
at_xdmac_write(atxdmac, AT_XDMAC_GRWR, atchan->mask);
11631172
clear_bit(AT_XDMAC_CHAN_IS_PAUSED, &atchan->status);
1164-
spin_unlock_bh(&atchan->lock);
1173+
spin_unlock_irqrestore(&atchan->lock, flags);
11651174

11661175
return 0;
11671176
}
@@ -1171,10 +1180,11 @@ static int at_xdmac_device_terminate_all(struct dma_chan *chan)
11711180
struct at_xdmac_desc *desc, *_desc;
11721181
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
11731182
struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device);
1183+
unsigned long flags;
11741184

11751185
dev_dbg(chan2dev(chan), "%s\n", __func__);
11761186

1177-
spin_lock_bh(&atchan->lock);
1187+
spin_lock_irqsave(&atchan->lock, flags);
11781188
at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
11791189
while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
11801190
cpu_relax();
@@ -1184,7 +1194,7 @@ static int at_xdmac_device_terminate_all(struct dma_chan *chan)
11841194
at_xdmac_remove_xfer(atchan, desc);
11851195

11861196
clear_bit(AT_XDMAC_CHAN_IS_CYCLIC, &atchan->status);
1187-
spin_unlock_bh(&atchan->lock);
1197+
spin_unlock_irqrestore(&atchan->lock, flags);
11881198

11891199
return 0;
11901200
}
@@ -1194,8 +1204,9 @@ static int at_xdmac_alloc_chan_resources(struct dma_chan *chan)
11941204
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
11951205
struct at_xdmac_desc *desc;
11961206
int i;
1207+
unsigned long flags;
11971208

1198-
spin_lock_bh(&atchan->lock);
1209+
spin_lock_irqsave(&atchan->lock, flags);
11991210

12001211
if (at_xdmac_chan_is_enabled(atchan)) {
12011212
dev_err(chan2dev(chan),
@@ -1226,7 +1237,7 @@ static int at_xdmac_alloc_chan_resources(struct dma_chan *chan)
12261237
dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
12271238

12281239
spin_unlock:
1229-
spin_unlock_bh(&atchan->lock);
1240+
spin_unlock_irqrestore(&atchan->lock, flags);
12301241
return i;
12311242
}
12321243

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