Messages in this thread Patch in this message |  | | From | Finn Thain <> | Subject | [PATCH 03/12] scsi/atari_scsi: Make device register accessors re-enterant | Date | Tue, 4 Oct 2016 01:40:50 -0400 (EDT) |
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This patch fixes an old bug: accesses to device registers from the interrupt handler (after reselection, DMA completion etc.) could mess up a device register access elsewhere, if the latter takes place outside of an irq lock (during selection etc.).
Signed-off-by: Finn Thain <fthain@telegraphics.com.au> --- drivers/scsi/atari_scsi.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c index a59ad94..862f30c 100644 --- a/drivers/scsi/atari_scsi.c +++ b/drivers/scsi/atari_scsi.c @@ -670,14 +670,26 @@ static void atari_scsi_tt_reg_write(unsigned char reg, unsigned char value) static unsigned char atari_scsi_falcon_reg_read(unsigned char reg) { - dma_wd.dma_mode_status= (u_short)(0x88 + reg); - return (u_char)dma_wd.fdc_acces_seccount; + unsigned long flags; + unsigned char result; + + reg += 0x88; + local_irq_save(flags); + dma_wd.dma_mode_status = (u_short)reg; + result = (u_char)dma_wd.fdc_acces_seccount; + local_irq_restore(flags); + return result; } static void atari_scsi_falcon_reg_write(unsigned char reg, unsigned char value) { - dma_wd.dma_mode_status = (u_short)(0x88 + reg); + unsigned long flags; + + reg += 0x88; + local_irq_save(flags); + dma_wd.dma_mode_status = (u_short)reg; dma_wd.fdc_acces_seccount = (u_short)value; + local_irq_restore(flags); } -- 2.7.3
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