Messages in this thread Patch in this message | | | Date | Wed, 26 Feb 2003 10:14:54 -0800 | From | Greg KH <> | Subject | Re: [PATCH 7/8] dm: __LOW macro fix no. 2 |
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On Wed, Feb 26, 2003 at 05:12:49PM +0000, Joe Thornber wrote: > Another fix for the __LOW macro. > > When dm_table and dm_target structures are initialized, the "limits" fields > (struct io_restrictions) are initialized to zero (e.g. in dm_table_add_target() > in dm-table.c). However, zero is not a useable value in these fields. The > request queue will never let an I/O through, regardless of how small it might > be, if max_sectors is set to zero (see generic_make_request in ll_rw_blk.c). > This change to the __LOW() macro sets these fields correctly when they are > first initialized. [Kevin Corry] > > --- diff/drivers/md/dm-table.c 2003-02-26 16:10:02.000000000 +0000 > +++ source/drivers/md/dm-table.c 2003-02-26 16:10:19.000000000 +0000 > @@ -79,7 +79,7 @@ > } > > #define __HIGH(l, r) if (*(l) < (r)) *(l) = (r) > -#define __LOW(l, r) if (*(l) > (r)) *(l) = (r) > +#define __LOW(l, r) if (*(l) == 0 || *(l) > (r)) *(l) = (r)
Any reason to not use the existing min() and max() macros instead of these? Then: __HIGH(foo, bar); can be written as: foo = max(foo, bar); which is (IMHO) easier to read.
By special casing the logic in your __LOW() macro, you're only asking for trouble in the long run :)
thanks,
greg k-h - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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