On Sat, Nov 12, 2022 at 02:49:35PM -0500, Douglas Gilbert wrote: > This patch fixes a check done by sgl_alloc_order() before it starts > any allocations. The comment in the original said: "Check for integer > overflow" but the right hand side of the expression in the condition > is resolved as u32 so it can not exceed UINT32_MAX (4 GiB) which > means 'length' can not exceed that value. > > This function may be used to replace vmalloc(unsigned long) for a > large allocation (e.g. a ramdisk). vmalloc has no limit at 4 GiB so > it seems unreasonable that sgl_alloc_order() whose length type is > unsigned long long should be limited to 4 GB. > > Solutions to this issue were discussed by Jason Gunthorpe > <jgg@xxxxxxxx> and Bodo Stroesser <bostroesser@xxxxxxxxx>. This > version is base on a linux-scsi post by Jason titled: "Re: > [PATCH v7 1/4] sgl_alloc_order: remove 4 GiB limit" dated 20220201. > > An earlier patch fixed a memory leak in sg_alloc_order() due to the > misuse of sgl_free(). Take the opportunity to put a one line comment > above sgl_free()'s declaration warning that it is not suitable when > order > 0 . > > Cc: Jason Gunthorpe <jgg@xxxxxxxx> > Cc: Bodo Stroesser <bostroesser@xxxxxxxxx> > Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx> > --- > include/linux/scatterlist.h | 1 + > lib/scatterlist.c | 23 ++++++++++++++--------- > 2 files changed, 15 insertions(+), 9 deletions(-) I still prefer the version I posted here: https://lore.kernel.org/linux-scsi/Y1aDQznakNaWD8kd@xxxxxxxx/ Jason
