From mboxrd@z Thu Jan 1 00:00:00 1970 From: rabin@rab.in (Rabin Vincent) Date: Sat, 1 Jan 2011 16:06:08 +0530 Subject: [PATCH] mmci: call flush_dcache_page() outside of atomic kmap Message-ID: <1293878168-12741-1-git-send-email-rabin@rab.in> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org While booting a QEMU Versatile/PB system with the root file system on SD, the following WARN_ON hits: ------------[ cut here ]------------ WARNING: at /home/rabin/kernel/arm/lib/scatterlist.c:426 sg_miter_stop+0x64/0x9c() Modules linked in: [] (unwind_backtrace+0x0/0xe4) from [] (warn_slowpath_common+0x4c/0x64) [] (warn_slowpath_common+0x4c/0x64) from [] (warn_slowpath_null+0x18/0x1c) [] (warn_slowpath_null+0x18/0x1c) from [] (sg_miter_stop+0x64/0x9c) [] (sg_miter_stop+0x64/0x9c) from [] (mmci_pio_irq+0x1fc/0x270) [] (mmci_pio_irq+0x1fc/0x270) from [] (handle_IRQ_event+0x24/0xf0) [] (handle_IRQ_event+0x24/0xf0) from [] (handle_level_irq+0xa4/0x114) [] (handle_level_irq+0xa4/0x114) from [] (sic_handle_irq+0x50/0x60) [] (sic_handle_irq+0x50/0x60) from [] (asm_do_IRQ+0x70/0x94) [] (asm_do_IRQ+0x70/0x94) from [] (__irq_svc+0x34/0xa0) It's the WARN_ON(!irqs_disabled()) in sg_miter_stop(): if (miter->__flags & SG_MITER_ATOMIC) { WARN_ON(!irqs_disabled()); kunmap_atomic(miter->addr, KM_BIO_SRC_IRQ); } This is because if the cache is VIVT, flush_dcache_page() calls __flush_dcache_aliases() when a user space mapping exists. That function uses flush_dcache_mmap_unlock() which is spin_unlock_irq(), which enables interrupts. Fix this by calling flush_dcache_page() only after the sg_miter is stopped. Signed-off-by: Rabin Vincent --- drivers/mmc/host/mmci.c | 25 ++++++++++++++++--------- 1 files changed, 16 insertions(+), 9 deletions(-) diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c index 0814b88..84a49ec 100644 --- a/drivers/mmc/host/mmci.c +++ b/drivers/mmc/host/mmci.c @@ -291,14 +291,18 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data, */ if (data->flags & MMC_DATA_READ) { struct sg_mapping_iter *sg_miter = &host->sg_miter; + struct page *page = NULL; unsigned long flags; local_irq_save(flags); if (sg_miter_next(sg_miter)) { - flush_dcache_page(sg_miter->page); + page = sg_miter->page; sg_miter_stop(sg_miter); } local_irq_restore(flags); + + if (page) + flush_dcache_page(page); } } @@ -487,17 +491,16 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id) struct sg_mapping_iter *sg_miter = &host->sg_miter; struct variant_data *variant = host->variant; void __iomem *base = host->base; - unsigned long flags; u32 status; status = readl(base + MMCISTATUS); dev_dbg(mmc_dev(host->mmc), "irq1 (pio) %08x\n", status); - local_irq_save(flags); - do { unsigned int remain, len; + unsigned long flags; + struct page *page; char *buffer; /* @@ -510,9 +513,13 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id) if (!(status & (MCI_TXFIFOHALFEMPTY|MCI_RXDATAAVLBL))) break; - if (!sg_miter_next(sg_miter)) + local_irq_save(flags); + if (!sg_miter_next(sg_miter)) { + local_irq_restore(flags); break; + } + page = sg_miter->page; buffer = sg_miter->addr; remain = sg_miter->length; @@ -527,18 +534,18 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id) host->size -= len; remain -= len; + sg_miter_stop(sg_miter); + local_irq_restore(flags); + if (remain) break; if (status & MCI_RXACTIVE) - flush_dcache_page(sg_miter->page); + flush_dcache_page(page); status = readl(base + MMCISTATUS); } while (1); - sg_miter_stop(sg_miter); - - local_irq_restore(flags); /* * If we're nearing the end of the read, switch to -- 1.7.2.3