Messages in this thread Patch in this message | | | Date | Tue, 12 Feb 2002 14:58:52 +0100 | From | Martin Dalecki <> | Subject | Re: another IDE cleanup: kill duplicated code |
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Vojtech Pavlik wrote:
>On Tue, Feb 12, 2002 at 02:17:48PM +0100, Martin Dalecki wrote: > >>So the conclusions is that not just the read_ahead array is bogous now. >>The max_readahead array can be killed entierly from the kernel as well ;-). >> >>The answer is: I'm now confident that you can just remove all the >>max_readahead initialization from the ide code. >> > >Since I've come to the same conclusion, here is the patch. It removes >read_ahead, max_readahead, BLKRAGET, BLKRASET, BLKFRAGET and BLKFRASET >completely. > Welcome the the "Write Only Variable" haters club ;-).
Please note that the lvm code is playing mental with himself on the lv_read_ahead struct member as well. This member get's set saved preserved, but it's never used nowhere there:
./include/linux/lvm.h: uint lv_read_ahead; ./include/linux/lvm.h: uint32_t lv_read_ahead; /* HM */
>diff -urN linux-2.5.4/drivers/block/ll_rw_blk.c linux-2.5.4-readahead/drivers/block/ll_rw_blk.c >--- linux-2.5.4/drivers/block/ll_rw_blk.c Thu Jan 31 16:45:20 2002 >+++ linux-2.5.4-readahead/drivers/block/ll_rw_blk.c Tue Feb 12 14:27:32 2002 >@@ -56,8 +56,6 @@ > > /* This specifies how many sectors to read ahead on the disk. */ > >-int read_ahead[MAX_BLKDEV]; >- >
You did miss the comment by shooting above!
>diff -urN linux-2.5.4/include/linux/fs.h linux-2.5.4-readahead/include/linux/fs.h >--- linux-2.5.4/include/linux/fs.h Tue Feb 12 12:22:54 2002 >+++ linux-2.5.4-readahead/include/linux/fs.h Tue Feb 12 14:32:32 2002 >@@ -173,10 +173,6 @@ > #define BLKRRPART _IO(0x12,95) /* re-read partition table */ > #define BLKGETSIZE _IO(0x12,96) /* return device size /512 (long *arg) */ > #define BLKFLSBUF _IO(0x12,97) /* flush buffer cache */ >-#define BLKRASET _IO(0x12,98) /* Set read ahead for block device */ >-#define BLKRAGET _IO(0x12,99) /* get current read ahead setting */ >-#define BLKFRASET _IO(0x12,100)/* set filesystem (mm/filemap.c) read-ahead */ >-#define BLKFRAGET _IO(0x12,101)/* get filesystem (mm/filemap.c) read-ahead */ > #define BLKSECTSET _IO(0x12,102)/* set max sectors per request (ll_rw_blk.c) */ > #define BLKSECTGET _IO(0x12,103)/* get max sectors per request (ll_rw_blk.c) */ > #define BLKSSZGET _IO(0x12,104)/* get block device sector size */ >@@ -1490,8 +1486,6 @@ >
I would rather suggest to to #if 0 ... #endif instead with a note about those values beeing no longer used.
>diff -urN linux-2.5.4/mm/filemap.c linux-2.5.4-readahead/mm/filemap.c >--- linux-2.5.4/mm/filemap.c Tue Feb 12 12:22:54 2002 >+++ linux-2.5.4-readahead/mm/filemap.c Tue Feb 12 14:29:58 2002 >@@ -1131,13 +1131,6 @@ > * 64k if defined (4K page size assumed). > */ > >-static inline int get_max_readahead(struct inode * inode) >-{ >- if (kdev_none(inode->i_dev) || !max_readahead[major(inode->i_dev)]) >- return MAX_READAHEAD; >- return max_readahead[major(inode->i_dev)][minor(inode->i_dev)]; >-} >- > static void generic_file_readahead(int reada_ok, > struct file * filp, struct inode * inode, > struct page * page) >@@ -1146,7 +1139,7 @@ > unsigned long index = page->index; > unsigned long max_ahead, ahead; > unsigned long raend; >- int max_readahead = get_max_readahead(inode); >+ int max_readahead = MAX_READAHEAD; >
This wonders me a bit, why you didn't just propagate the constant deeper.
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