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Commit 70ec3bb8 authored by Julia Lawall's avatar Julia Lawall Committed by David Woodhouse
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mtd: Use BLOCK_NIL consistently in NFTL/INFTL 

Use BLOCK_NIL consistently rather than sometimes 0xffff and sometimes
BLOCK_NIL.

The semantic patch that finds this issue is below
(http://www.emn.fr/x-info/coccinelle/

).  On the other hand, the changes
were made by hand, in part because drivers/mtd/inftlcore.c contains dead
code that causes spatch to ignore a relevant function.  Specifically, the
function INFTL_findwriteunit contains a do-while loop, but always takes a
return that leaves the loop on the first iteration.

// <smpl>
@r exists@
identifier f,C;
@@

f(...) { ... return C; }

@s@
identifier r.C;
expression E;
@@

@@
identifier r.f,r.C,I;
expression s.E;
@@

f(...) {
 <...
(
  I
|
- E
+ C
)
 ...>
}

// </smpl>

Signed-off-by: default avatarJulia Lawall <julia@diku.dk>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 89bb871e

drivers/mtd/inftlcore.c

+6 −5
Original line number Diff line number Diff line
@@ -226,7 +226,7 @@ static u16 INFTL_findfreeblock(struct INFTLrecord *inftl, int desperate) 
	if (!desperate && inftl->numfreeEUNs < 2) {

		DEBUG(MTD_DEBUG_LEVEL1, "INFTL: there are too few free "

			"EUNs (%d)\n", inftl->numfreeEUNs);

		return 0xffff;

		return BLOCK_NIL;

	}



	/* Scan for a free block */
@@ -281,7 +281,8 @@ static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned 
	silly = MAX_LOOPS;

	while (thisEUN < inftl->nb_blocks) {

		for (block = 0; block < inftl->EraseSize/SECTORSIZE; block ++) {

			if ((BlockMap[block] != 0xffff) || BlockDeleted[block])

			if ((BlockMap[block] != BLOCK_NIL) ||

			    BlockDeleted[block])

				continue;



			if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize)
@@ -525,7 +526,7 @@ static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block) 
			if (!silly--) {

				printk(KERN_WARNING "INFTL: infinite loop in "

					"Virtual Unit Chain 0x%x\n", thisVUC);

				return 0xffff;

				return BLOCK_NIL;

			}



			/* Skip to next block in chain */
@@ -549,7 +550,7 @@ static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block) 
			 * waiting to be picked up. We're going to have to fold

			 * a chain to make room.

			 */

			thisEUN = INFTL_makefreeblock(inftl, 0xffff);

			thisEUN = INFTL_makefreeblock(inftl, BLOCK_NIL);



			/*

			 * Hopefully we free something, lets try again.
@@ -631,7 +632,7 @@ static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block) 


	printk(KERN_WARNING "INFTL: error folding to make room for Virtual "

		"Unit Chain 0x%x\n", thisVUC);

	return 0xffff;

	return BLOCK_NIL;

}



/*

drivers/mtd/nftlcore.c

+8 −8
Original line number Diff line number Diff line
@@ -208,7 +208,7 @@ static u16 NFTL_findfreeblock(struct NFTLrecord *nftl, int desperate ) 
	/* Normally, we force a fold to happen before we run out of free blocks completely */

	if (!desperate && nftl->numfreeEUNs < 2) {

		DEBUG(MTD_DEBUG_LEVEL1, "NFTL_findfreeblock: there are too few free EUNs\n");

		return 0xffff;

		return BLOCK_NIL;

	}



	/* Scan for a free block */
@@ -230,11 +230,11 @@ static u16 NFTL_findfreeblock(struct NFTLrecord *nftl, int desperate ) 
			printk("Argh! No free blocks found! LastFreeEUN = %d, "

			       "FirstEUN = %d\n", nftl->LastFreeEUN,

			       le16_to_cpu(nftl->MediaHdr.FirstPhysicalEUN));

			return 0xffff;

			return BLOCK_NIL;

		}

	} while (pot != nftl->LastFreeEUN);



	return 0xffff;

	return BLOCK_NIL;

}



static u16 NFTL_foldchain (struct NFTLrecord *nftl, unsigned thisVUC, unsigned pendingblock )
@@ -431,7 +431,7 @@ static u16 NFTL_foldchain (struct NFTLrecord *nftl, unsigned thisVUC, unsigned p 


	/* add the header so that it is now a valid chain */

	oob.u.a.VirtUnitNum = oob.u.a.SpareVirtUnitNum = cpu_to_le16(thisVUC);

	oob.u.a.ReplUnitNum = oob.u.a.SpareReplUnitNum = 0xffff;

	oob.u.a.ReplUnitNum = oob.u.a.SpareReplUnitNum = BLOCK_NIL;



	nftl_write_oob(mtd, (nftl->EraseSize * targetEUN) + 8,

		       8, &retlen, (char *)&oob.u);
@@ -515,7 +515,7 @@ static u16 NFTL_makefreeblock( struct NFTLrecord *nftl , unsigned pendingblock) 
	if (ChainLength < 2) {

		printk(KERN_WARNING "No Virtual Unit Chains available for folding. "

		       "Failing request\n");

		return 0xffff;

		return BLOCK_NIL;

	}



	return NFTL_foldchain (nftl, LongestChain, pendingblock);
@@ -578,7 +578,7 @@ static inline u16 NFTL_findwriteunit(struct NFTLrecord *nftl, unsigned block) 
				printk(KERN_WARNING

				       "Infinite loop in Virtual Unit Chain 0x%x\n",

				       thisVUC);

				return 0xffff;

				return BLOCK_NIL;

			}



			/* Skip to next block in chain */
@@ -601,7 +601,7 @@ static inline u16 NFTL_findwriteunit(struct NFTLrecord *nftl, unsigned block) 
			//u16 startEUN = nftl->EUNtable[thisVUC];



			//printk("Write to VirtualUnitChain %d, calling makefreeblock()\n", thisVUC);

			writeEUN = NFTL_makefreeblock(nftl, 0xffff);

			writeEUN = NFTL_makefreeblock(nftl, BLOCK_NIL);



			if (writeEUN == BLOCK_NIL) {

				/* OK, we accept that the above comment is
@@ -673,7 +673,7 @@ static inline u16 NFTL_findwriteunit(struct NFTLrecord *nftl, unsigned block) 


	printk(KERN_WARNING "Error folding to make room for Virtual Unit Chain 0x%x\n",

	       thisVUC);

	return 0xffff;

	return BLOCK_NIL;

}



static int nftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,