| Message ID | 20191008075022.30055-17-dgilbert@interlog.com (mailing list archive) |
|---|---|
| State | Deferred |
| Headers | show |
| Series | sg: add v4 interface | expand |
On 10/8/19 9:50 AM, Douglas Gilbert wrote: > Simple refactoring of the sg_vma_fault() function. > > Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> > --- > drivers/scsi/sg.c | 33 +++++++++++++++++++++++---------- > 1 file changed, 23 insertions(+), 10 deletions(-) > > diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c > index 903faafaeff9..befcbfbcece1 100644 > --- a/drivers/scsi/sg.c > +++ b/drivers/scsi/sg.c > @@ -1389,14 +1389,16 @@ sg_fasync(int fd, struct file *filp, int mode) > return fasync_helper(fd, filp, mode, &sfp->async_qp); > } > > +/* Note: the error return: VM_FAULT_SIGBUS causes a "bus error" */ > static vm_fault_t > sg_vma_fault(struct vm_fault *vmf) > { > - struct vm_area_struct *vma = vmf->vma; > - struct sg_fd *sfp; > + int k, length; > unsigned long offset, len, sa; > + struct vm_area_struct *vma = vmf->vma; > struct sg_scatter_hold *rsv_schp; > - int k, length; > + struct sg_device *sdp; > + struct sg_fd *sfp; > const char *nbp = "==NULL, bad"; > > if (!vma) { Of course, one would prefer normal kernel-doc style for the comment ... Otherwise: Reviewed-by: Hannes Reinecke <hare@suse.com> Cheers, Hannes
On 2019-10-18 6:17 a.m., Hannes Reinecke wrote: > On 10/8/19 9:50 AM, Douglas Gilbert wrote: >> Simple refactoring of the sg_vma_fault() function. >> >> Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> >> --- >> drivers/scsi/sg.c | 33 +++++++++++++++++++++++---------- >> 1 file changed, 23 insertions(+), 10 deletions(-) >> >> diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c >> index 903faafaeff9..befcbfbcece1 100644 >> --- a/drivers/scsi/sg.c >> +++ b/drivers/scsi/sg.c >> @@ -1389,14 +1389,16 @@ sg_fasync(int fd, struct file *filp, int mode) >> return fasync_helper(fd, filp, mode, &sfp->async_qp); >> } >> >> +/* Note: the error return: VM_FAULT_SIGBUS causes a "bus error" */ >> static vm_fault_t >> sg_vma_fault(struct vm_fault *vmf) >> { >> - struct vm_area_struct *vma = vmf->vma; >> - struct sg_fd *sfp; >> + int k, length; >> unsigned long offset, len, sa; >> + struct vm_area_struct *vma = vmf->vma; >> struct sg_scatter_hold *rsv_schp; >> - int k, length; >> + struct sg_device *sdp; >> + struct sg_fd *sfp; >> const char *nbp = "==NULL, bad"; >> >> if (!vma) { > Of course, one would prefer normal kernel-doc style for the comment ... For static functions, that is left up to the discretion of the maintainer, according to the document to which you refer :-) I prefer comments that aren't compilable, IOWs that don't state the bleeding obvious. While I was debugging sg_vma_fault() it took me a while to understand why my test harness was crashing, hence that comment. Doug Gilbert sg_vma_fault( > Otherwise: > Reviewed-by: Hannes Reinecke <hare@suse.com> > > Cheers, > > Hannes >
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c index 903faafaeff9..befcbfbcece1 100644 --- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1389,14 +1389,16 @@ sg_fasync(int fd, struct file *filp, int mode) return fasync_helper(fd, filp, mode, &sfp->async_qp); } +/* Note: the error return: VM_FAULT_SIGBUS causes a "bus error" */ static vm_fault_t sg_vma_fault(struct vm_fault *vmf) { - struct vm_area_struct *vma = vmf->vma; - struct sg_fd *sfp; + int k, length; unsigned long offset, len, sa; + struct vm_area_struct *vma = vmf->vma; struct sg_scatter_hold *rsv_schp; - int k, length; + struct sg_device *sdp; + struct sg_fd *sfp; const char *nbp = "==NULL, bad"; if (!vma) { @@ -1408,20 +1410,31 @@ sg_vma_fault(struct vm_fault *vmf) pr_warn("%s: sfp%s\n", __func__, nbp); goto out_err; } + sdp = sfp->parentdp; + if (sdp && unlikely(SG_IS_DETACHING(sdp))) { + SG_LOG(1, sfp, "%s: device detaching\n", __func__); + goto out_err; + } rsv_schp = &sfp->reserve; offset = vmf->pgoff << PAGE_SHIFT; - if (offset >= rsv_schp->buflen) - return VM_FAULT_SIGBUS; + if (offset >= (unsigned int)rsv_schp->buflen) { + SG_LOG(1, sfp, "%s: offset[%lu] >= rsv.buflen\n", __func__, + offset); + goto out_err; + } sa = vma->vm_start; SG_LOG(3, sfp, "%s: vm_start=0x%lx, off=%lu\n", __func__, sa, offset); length = 1 << (PAGE_SHIFT + rsv_schp->page_order); - for (k = 0; k < rsv_schp->num_sgat && sa < vma->vm_end; k++) { + for (k = 0; k < rsv_schp->num_sgat && sa < vma->vm_end; ++k) { len = vma->vm_end - sa; - len = (len < length) ? len : length; + len = min_t(int, len, (int)length); if (offset < len) { - struct page *page = nth_page(rsv_schp->pages[k], - offset >> PAGE_SHIFT); - get_page(page); /* increment page count */ + struct page *page; + struct page *pp; + + pp = rsv_schp->pages[k]; + page = nth_page(pp, offset >> PAGE_SHIFT); + get_page(page); /* increment page count */ vmf->page = page; return 0; /* success */ }
Simple refactoring of the sg_vma_fault() function. Signed-off-by: Douglas Gilbert <dgilbert@interlog.com> --- drivers/scsi/sg.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-)