Message ID | 20130809094904.GC29282@elgon.mountain |
---|---|
State | Accepted |
Commit | daae74cad4bcd4566fcb82477e33c42bcdaa86e8 |
Headers | show |
于 2013年08月09日 17:49, Dan Carpenter 写道: > There are static checkers which complain when we declare variables as could you tell me which "checker" and how do you test it? you'd better post the warning message here. thanks Huang Shijie > 64 bit bitfields but only use the lower 32 bits because of shift > wrapping. In this case "len" is declared as u64 as opposed to unsigned > long or something which might be 32 bits. > > Signed-off-by: Dan Carpenter<dan.carpenter@oracle.com> > > diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c > index 9a48758..3eddd04 100644 > --- a/drivers/mtd/nand/nand_base.c > +++ b/drivers/mtd/nand/nand_base.c > @@ -108,13 +108,13 @@ static int check_offs_len(struct mtd_info *mtd, > int ret = 0; > > /* Start address must align on block boundary */ > - if (ofs& ((1<< chip->phys_erase_shift) - 1)) { > + if (ofs& ((1ULL<< chip->phys_erase_shift) - 1)) { > pr_debug("%s: unaligned address\n", __func__); > ret = -EINVAL; > } > > /* Length must align on block boundary */ > - if (len& ((1<< chip->phys_erase_shift) - 1)) { > + if (len& ((1ULL<< chip->phys_erase_shift) - 1)) { > pr_debug("%s: length not block aligned\n", __func__); > ret = -EINVAL; > } > @@ -394,7 +394,7 @@ static int nand_block_markbad_lowlevel(struct mtd_info *mtd, loff_t ofs) > memset(&einfo, 0, sizeof(einfo)); > einfo.mtd = mtd; > einfo.addr = ofs; > - einfo.len = 1<< chip->phys_erase_shift; > + einfo.len = 1ULL<< chip->phys_erase_shift; > nand_erase_nand(mtd,&einfo, 0); > > /* Write bad block marker to OOB */ > @@ -2630,7 +2630,7 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr, > } > > /* Increment page address and decrement length */ > - len -= (1<< chip->phys_erase_shift); > + len -= (1ULL<< chip->phys_erase_shift); > page += pages_per_block; > > /* Check, if we cross a chip boundary */ >
On Tue, Aug 13, 2013 at 02:23:02PM +0800, Huang Shijie wrote: > 于 2013年08月09日 17:49, Dan Carpenter 写道: > >There are static checkers which complain when we declare variables as > > could you tell me which "checker" and how do you test it? > > you'd better post the warning message here. > It's some stuff I'm working on but haven't released yet. But "len" and "ofs" are declared as u64 and loff_t. If they were declared as unsigned long then maybe the current code would be fine because the code would be correct-ish on 32 bit arches. So this is definitely the right thing to do. regards, dan carpenter
On 08/12/2013 11:35 PM, Dan Carpenter wrote: > On Tue, Aug 13, 2013 at 02:23:02PM +0800, Huang Shijie wrote: >> 于 2013年08月09日 17:49, Dan Carpenter 写道: >>> There are static checkers which complain when we declare variables as >> >> could you tell me which "checker" and how do you test it? >> >> you'd better post the warning message here. >> > > It's some stuff I'm working on but haven't released yet. But "len" Which static checker isn't all that important, so no worries. The patch can stand on its own merits. > and "ofs" are declared as u64 and loff_t. If they were declared as > unsigned long then maybe the current code would be fine because the > code would be correct-ish on 32 bit arches. IIUC, it's still correct, since we surely will never have an eraseblock size near 4GB (i.e., if the shift is ever larger than 31, we have a bug somewhere else). > So this is definitely the right thing to do. As far as types are concerned, yes, this is still the right thing to do. Brian
On Fri, 2013-08-09 at 12:49 +0300, Dan Carpenter wrote: > There are static checkers which complain when we declare variables as > 64 bit bitfields but only use the lower 32 bits because of shift > wrapping. In this case "len" is declared as u64 as opposed to unsigned > long or something which might be 32 bits. > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Pushed to l2-mtd.git, thanks!
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 9a48758..3eddd04 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -108,13 +108,13 @@ static int check_offs_len(struct mtd_info *mtd, int ret = 0; /* Start address must align on block boundary */ - if (ofs & ((1 << chip->phys_erase_shift) - 1)) { + if (ofs & ((1ULL << chip->phys_erase_shift) - 1)) { pr_debug("%s: unaligned address\n", __func__); ret = -EINVAL; } /* Length must align on block boundary */ - if (len & ((1 << chip->phys_erase_shift) - 1)) { + if (len & ((1ULL << chip->phys_erase_shift) - 1)) { pr_debug("%s: length not block aligned\n", __func__); ret = -EINVAL; } @@ -394,7 +394,7 @@ static int nand_block_markbad_lowlevel(struct mtd_info *mtd, loff_t ofs) memset(&einfo, 0, sizeof(einfo)); einfo.mtd = mtd; einfo.addr = ofs; - einfo.len = 1 << chip->phys_erase_shift; + einfo.len = 1ULL << chip->phys_erase_shift; nand_erase_nand(mtd, &einfo, 0); /* Write bad block marker to OOB */ @@ -2630,7 +2630,7 @@ int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr, } /* Increment page address and decrement length */ - len -= (1 << chip->phys_erase_shift); + len -= (1ULL << chip->phys_erase_shift); page += pages_per_block; /* Check, if we cross a chip boundary */
There are static checkers which complain when we declare variables as 64 bit bitfields but only use the lower 32 bits because of shift wrapping. In this case "len" is declared as u64 as opposed to unsigned long or something which might be 32 bits. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>