[PATCH] mmci: call flush_dcache_page() outside of atomic kmap
From: Rabin Vincent <hidden>
Date: 2011-01-01 10:36:08
Subsystem:
arm primecell mmci pl180/1 driver, multimedia card (mmc), secure digital (sd) and sdio subsystem, the rest · Maintainers:
Russell King, Ulf Hansson, Linus Torvalds
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:
[<c0031da4>] (unwind_backtrace+0x0/0xe4) from [<c003d5c0>] (warn_slowpath_common+0x4c/0x64)
[<c003d5c0>] (warn_slowpath_common+0x4c/0x64) from [<c003d5f0>] (warn_slowpath_null+0x18/0x1c)
[<c003d5f0>] (warn_slowpath_null+0x18/0x1c) from [<c0148338>] (sg_miter_stop+0x64/0x9c)
[<c0148338>] (sg_miter_stop+0x64/0x9c) from [<c01a892c>] (mmci_pio_irq+0x1fc/0x270)
[<c01a892c>] (mmci_pio_irq+0x1fc/0x270) from [<c0065928>] (handle_IRQ_event+0x24/0xf0)
[<c0065928>] (handle_IRQ_event+0x24/0xf0) from [<c0067930>] (handle_level_irq+0xa4/0x114)
[<c0067930>] (handle_level_irq+0xa4/0x114) from [<c0036258>] (sic_handle_irq+0x50/0x60)
[<c0036258>] (sic_handle_irq+0x50/0x60) from [<c0022070>] (asm_do_IRQ+0x70/0x94)
[<c0022070>] (asm_do_IRQ+0x70/0x94) from [<c002c0b4>] (__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 <redacted>
---
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