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authorDavid Brownell <dbrownell@users.sourceforge.net>2008-09-02 17:35:46 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-09-02 22:21:38 -0400
commite385ea63f44b475e034a78b6d8bc6bb50caf72ca (patch)
tree11b1a9122920c596f76ddf7ae0ac288f36f51ec2 /drivers/mmc/host/at91_mci.c
parent363f66fe06c75270b669c88e321e6b354ba0201e (diff)
mmc: at91_mci: don't use coherent dma buffers
At91_mci is abusing dma_free_coherent(), which may not be called with IRQs disabled. I saw "mkfs.ext3" on an MMC card objecting voluminously as each write completed: WARNING: at arch/arm/mm/consistent.c:368 dma_free_coherent+0x2c/0x224() [<c002726c>] (dump_stack+0x0/0x14) from [<c00387d4>] (warn_on_slowpath+0x4c/0x68) [<c0038788>] (warn_on_slowpath+0x0/0x68) from [<c0028768>] (dma_free_coherent+0x2c/0x224) r6:00008008 r5:ffc06000 r4:00000000 [<c002873c>] (dma_free_coherent+0x0/0x224) from [<c01918ac>] (at91_mci_irq+0x374/0x420) [<c0191538>] (at91_mci_irq+0x0/0x420) from [<c0065d9c>] (handle_IRQ_event+0x2c/0x6c) ... This bug has been around for a LONG time. The MM warning is from late 2005, but the driver merged a year later ... so I'm puzzled why nobody noticed this before now. The fix involves noting that this buffer shouldn't be DMA-coherent; it's just used for normal DMA writes. So replace it with standard kmalloc() buffering and DMA mapping calls. This is the quickie fix. A better one would not rely on allocating large bounce buffers. (Note that dma_alloc_coherent could have failed too, but that case was ignored... kmalloc is a bit more likely to fail though.) Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Pierre Ossman <drzeus-mmc@drzeus.cx> Cc: Andrew Victor <linux@maxim.org.za> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/mmc/host/at91_mci.c')
-rw-r--r--drivers/mmc/host/at91_mci.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/mmc/host/at91_mci.c b/drivers/mmc/host/at91_mci.c
index 6915f40ac8ab..1f8b5b36222c 100644
--- a/drivers/mmc/host/at91_mci.c
+++ b/drivers/mmc/host/at91_mci.c
@@ -621,12 +621,21 @@ static void at91_mci_send_command(struct at91mci_host *host, struct mmc_command
621 if (cpu_is_at91sam9260 () || cpu_is_at91sam9263()) 621 if (cpu_is_at91sam9260 () || cpu_is_at91sam9263())
622 if (host->total_length < 12) 622 if (host->total_length < 12)
623 host->total_length = 12; 623 host->total_length = 12;
624 host->buffer = dma_alloc_coherent(NULL, 624
625 host->total_length, 625 host->buffer = kmalloc(host->total_length, GFP_KERNEL);
626 &host->physical_address, GFP_KERNEL); 626 if (!host->buffer) {
627 pr_debug("Can't alloc tx buffer\n");
628 cmd->error = -ENOMEM;
629 mmc_request_done(host->mmc, host->request);
630 return;
631 }
627 632
628 at91_mci_sg_to_dma(host, data); 633 at91_mci_sg_to_dma(host, data);
629 634
635 host->physical_address = dma_map_single(NULL,
636 host->buffer, host->total_length,
637 DMA_TO_DEVICE);
638
630 pr_debug("Transmitting %d bytes\n", host->total_length); 639 pr_debug("Transmitting %d bytes\n", host->total_length);
631 640
632 at91_mci_write(host, ATMEL_PDC_TPR, host->physical_address); 641 at91_mci_write(host, ATMEL_PDC_TPR, host->physical_address);
@@ -694,7 +703,10 @@ static void at91_mci_completed_command(struct at91mci_host *host, unsigned int s
694 cmd->resp[3] = at91_mci_read(host, AT91_MCI_RSPR(3)); 703 cmd->resp[3] = at91_mci_read(host, AT91_MCI_RSPR(3));
695 704
696 if (host->buffer) { 705 if (host->buffer) {
697 dma_free_coherent(NULL, host->total_length, host->buffer, host->physical_address); 706 dma_unmap_single(NULL,
707 host->physical_address, host->total_length,
708 DMA_TO_DEVICE);
709 kfree(host->buffer);
698 host->buffer = NULL; 710 host->buffer = NULL;
699 } 711 }
700 712