| Message ID | EAF47CD23C76F840A9E7FCE10091EFAB02A93B8033@dbde02.ent.ti.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 77d75dad3c728ec6c6822c6c2a131c4dc3123fde |
| Headers | show |
Hi Tony, I wonder, what happened to this patch? Shilimkar, Santosh wrote: > From: Santosh Shilimkar <santosh.shilimkar@ti.com> > > Fix the possible race condition in omap_free_dma(). Function omap_free_dma() > sets the dev_id = -1 and then accesses the channel afterwards to clear it. > But setting the dev_id=-1 makes the channel available for allocation again. > So it is possible someone else can grab it and results are unpredictable. > To avod this DMA channle is cleared first and then the dev_id = -1 is set. > > Thanks to McNeil, Sean <sean.mcneil@ti.com> for ointing out this issue. > > Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> > --- > arch/arm/plat-omap/dma.c | 13 ++++++------- > 1 files changed, 6 insertions(+), 7 deletions(-) > > Index: omapkernel/arch/arm/plat-omap/dma.c > =================================================================== > --- omapkernel.orig/arch/arm/plat-omap/dma.c > +++ omapkernel/arch/arm/plat-omap/dma.c > @@ -785,19 +785,12 @@ void omap_free_dma(int lch) > { > unsigned long flags; > > - spin_lock_irqsave(&dma_chan_lock, flags); > if (dma_chan[lch].dev_id == -1) { > pr_err("omap_dma: trying to free unallocated DMA channel %d\n", > lch); > - spin_unlock_irqrestore(&dma_chan_lock, flags); > return; > } > > - dma_chan[lch].dev_id = -1; > - dma_chan[lch].next_lch = -1; > - dma_chan[lch].callback = NULL; > - spin_unlock_irqrestore(&dma_chan_lock, flags); > - > if (cpu_class_is_omap1()) { > /* Disable all DMA interrupts for the channel. */ > dma_write(0, CICR(lch)); > @@ -823,6 +816,12 @@ void omap_free_dma(int lch) > dma_write(0, CCR(lch)); > omap_clear_dma(lch); > } > + > + spin_lock_irqsave(&dma_chan_lock, flags); > + dma_chan[lch].dev_id = -1; > + dma_chan[lch].next_lch = -1; > + dma_chan[lch].callback = NULL; > + spin_unlock_irqrestore(&dma_chan_lock, flags); > } > EXPORT_SYMBOL(omap_free_dma); > > > Regards, > Santosh > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
This patch has been applied to the linux-omap by youw fwiendly patch wobot. Initial commit ID (Likely to change): 77d75dad3c728ec6c6822c6c2a131c4dc3123fde PatchWorks http://patchwork.kernel.org/patch/14966/ Git http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=commit;h=77d75dad3c728ec6c6822c6c2a131c4dc3123fde -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: omapkernel/arch/arm/plat-omap/dma.c =================================================================== --- omapkernel.orig/arch/arm/plat-omap/dma.c +++ omapkernel/arch/arm/plat-omap/dma.c @@ -785,19 +785,12 @@ void omap_free_dma(int lch) { unsigned long flags; - spin_lock_irqsave(&dma_chan_lock, flags); if (dma_chan[lch].dev_id == -1) { pr_err("omap_dma: trying to free unallocated DMA channel %d\n", lch); - spin_unlock_irqrestore(&dma_chan_lock, flags); return; } - dma_chan[lch].dev_id = -1; - dma_chan[lch].next_lch = -1; - dma_chan[lch].callback = NULL; - spin_unlock_irqrestore(&dma_chan_lock, flags); - if (cpu_class_is_omap1()) { /* Disable all DMA interrupts for the channel. */ dma_write(0, CICR(lch)); @@ -823,6 +816,12 @@ void omap_free_dma(int lch) dma_write(0, CCR(lch)); omap_clear_dma(lch); } + + spin_lock_irqsave(&dma_chan_lock, flags); + dma_chan[lch].dev_id = -1; + dma_chan[lch].next_lch = -1; + dma_chan[lch].callback = NULL; + spin_unlock_irqrestore(&dma_chan_lock, flags); } EXPORT_SYMBOL(omap_free_dma);