Commit e847679b authored by Bartlomiej Zolnierkiewicz's avatar Bartlomiej Zolnierkiewicz Committed by Linus Torvalds

[PATCH] remove duplicated defines from ide.h

[trivia] Remove duplicated defines of PRD_BYTES and PRD_ENTRIES.
parent 9321751c
...@@ -227,25 +227,6 @@ typedef unsigned char byte; /* used everywhere */ ...@@ -227,25 +227,6 @@ typedef unsigned char byte; /* used everywhere */
#define PRD_BYTES 8 #define PRD_BYTES 8
#define PRD_ENTRIES (PAGE_SIZE / (2 * PRD_BYTES)) #define PRD_ENTRIES (PAGE_SIZE / (2 * PRD_BYTES))
/*
* Our Physical Region Descriptor (PRD) table should be large enough
* to handle the biggest I/O request we are likely to see. Since requests
* can have no more than 256 sectors, and since the typical blocksize is
* two or more sectors, we could get by with a limit of 128 entries here for
* the usual worst case. Most requests seem to include some contiguous blocks,
* further reducing the number of table entries required.
*
* The driver reverts to PIO mode for individual requests that exceed
* this limit (possible with 512 byte blocksizes, eg. MSDOS f/s), so handling
* 100% of all crazy scenarios here is not necessary.
*
* As it turns out though, we must allocate a full 4KB page for this,
* so the two PRD tables (ide0 & ide1) will each get half of that,
* allowing each to have about 256 entries (8 bytes each) from this.
*/
#define PRD_BYTES 8
#define PRD_ENTRIES (PAGE_SIZE / (2 * PRD_BYTES))
/* /*
* Some more useful definitions * Some more useful definitions
*/ */
......
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