Messages in this thread |  | | Date | Thu, 13 Mar 2003 11:28:54 +0100 | From | Jens Axboe <> | Subject | Re: [PATCH] bug in 2.4 bh_kmap_irq() breaks IDE under preempt patch |
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On Thu, Mar 13 2003, Marc-Christian Petersen wrote: > On Thursday 13 March 2003 10:26, Jens Axboe wrote: > > Hi Jens, > > > There's a tiny bit missing from your patch: > > > - * it's a highmem page > > > - */ > > > - __cli(); > > > + local_irq_save(*flags); > > > > local_irq_disable(); > > > > > addr = (unsigned long) kmap_atomic(bh->b_page, KM_BH_IRQ); > > > > > > - if (addr & ~PAGE_MASK) > > > - BUG(); > > > + BUG_ON (addr & ~PAGE_MASK); > > > > > > return (char *) addr + bh_offset(bh); > > > } > > > @@ -58,7 +46,7 @@ > > > unsigned long ptr = (unsigned long) buffer & PAGE_MASK; > > > > > > kunmap_atomic((void *) ptr, KM_BH_IRQ); > > > - __restore_flags(*flags); > > > + local_irq_restore(*flags); > local_irq_enable(); > > ^ isn't this missing too with your suggested one-liner?
no, the local_irq_restore() brings back the irq flags from before we did the irq disable. if interrupts were disabled before bh_kmap_irq() was called, we must not enable them. basically, maintain the same flags.
-- Jens Axboe
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