| Message ID | 20201120092251.2197-1-thunder.leizhen@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/1] device-dax: avoid an unnecessary check in alloc_dev_dax_range() | expand |
On Fri, Nov 20, 2020 at 1:23 AM Zhen Lei <thunder.leizhen@huawei.com> wrote: > > Swap the calling sequence of krealloc() and __request_region(), call the > latter first. In this way, the value of dev_dax->nr_range does not need to > be considered when __request_region() failed. This looks ok, but I think I want to see another cleanup go in first before this to add a helper for trimming the last range off the set of ranges: static void dev_dax_trim_range(struct dev_dax *dev_dax) { int i = dev_dax->nr_range - 1; struct range *range = &dev_dax->ranges[i].range; struct dax_region *dax_region = dev_dax->region; dev_dbg(dev, "delete range[%d]: %#llx:%#llx\n", i, (unsigned long long)range->start, (unsigned long long)range->end); __release_region(&dax_region->res, range->start, range_len(range)); if (--dev_dax->nr_range == 0) { kfree(dev_dax->ranges); dev_dax->ranges = NULL; } } Care to do a lead in patch with that cleanup, then do this one? I think that might also cleanup a memory leak report from Jane in addition to not needing the "goto" as well. http://lore.kernel.org/r/c8a8a260-34c6-dbfc-1f19-25c23d01cb45@oracle.com
On 2020/12/18 11:10, Dan Williams wrote: > On Fri, Nov 20, 2020 at 1:23 AM Zhen Lei <thunder.leizhen@huawei.com> wrote: >> >> Swap the calling sequence of krealloc() and __request_region(), call the >> latter first. In this way, the value of dev_dax->nr_range does not need to >> be considered when __request_region() failed. > > This looks ok, but I think I want to see another cleanup go in first > before this to add a helper for trimming the last range off the set of > ranges: > > static void dev_dax_trim_range(struct dev_dax *dev_dax) > { > int i = dev_dax->nr_range - 1; > struct range *range = &dev_dax->ranges[i].range; > struct dax_region *dax_region = dev_dax->region; > > dev_dbg(dev, "delete range[%d]: %#llx:%#llx\n", i, > (unsigned long long)range->start, > (unsigned long long)range->end); > > __release_region(&dax_region->res, range->start, range_len(range)); > if (--dev_dax->nr_range == 0) { > kfree(dev_dax->ranges); > dev_dax->ranges = NULL; > } > } > > Care to do a lead in patch with that cleanup, then do this one? I don't mind! You can add above helper first. After that, I'll update and send this patch again. > > I think that might also cleanup a memory leak report from Jane in > addition to not needing the "goto" as well. > > http://lore.kernel.org/r/c8a8a260-34c6-dbfc-1f19-25c23d01cb45@oracle.com > > . >
On 2020/11/20 17:22, Zhen Lei wrote: > Swap the calling sequence of krealloc() and __request_region(), call the > latter first. In this way, the value of dev_dax->nr_range does not need to > be considered when __request_region() failed. > > Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> > --- > drivers/dax/bus.c | 29 ++++++++++++----------------- > 1 file changed, 12 insertions(+), 17 deletions(-) > > diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c > index 27513d311242..1efae11d947a 100644 > --- a/drivers/dax/bus.c > +++ b/drivers/dax/bus.c > @@ -763,23 +763,15 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, > return 0; > } > > - ranges = krealloc(dev_dax->ranges, sizeof(*ranges) > - * (dev_dax->nr_range + 1), GFP_KERNEL); > - if (!ranges) > - return -ENOMEM; > - > alloc = __request_region(res, start, size, dev_name(dev), 0); > - if (!alloc) { > - /* > - * If this was an empty set of ranges nothing else > - * will release @ranges, so do it now. > - */ > - if (!dev_dax->nr_range) { > - kfree(ranges); > - ranges = NULL; > - } > - dev_dax->ranges = ranges; > + if (!alloc) > return -ENOMEM; > + > + ranges = krealloc(dev_dax->ranges, sizeof(*ranges) > + * (dev_dax->nr_range + 1), GFP_KERNEL); > + if (!ranges) { > + rc = -ENOMEM; > + goto err; Hi, Dan Williams: In fact, after adding the new helper dev_dax_trim_range(), we can directly call __release_region() and return error code at here. Replace goto. > } > > for (i = 0; i < dev_dax->nr_range; i++) > @@ -808,11 +800,14 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, > dev_dbg(dev, "delete range[%d]: %pa:%pa\n", dev_dax->nr_range - 1, > &alloc->start, &alloc->end); > dev_dax->nr_range--; > - __release_region(res, alloc->start, resource_size(alloc)); > - return rc; > + goto err; > } > > return 0; > + > +err: > + __release_region(res, alloc->start, resource_size(alloc)); > + return rc; > } > > static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size) >
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 27513d311242..1efae11d947a 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -763,23 +763,15 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, return 0; } - ranges = krealloc(dev_dax->ranges, sizeof(*ranges) - * (dev_dax->nr_range + 1), GFP_KERNEL); - if (!ranges) - return -ENOMEM; - alloc = __request_region(res, start, size, dev_name(dev), 0); - if (!alloc) { - /* - * If this was an empty set of ranges nothing else - * will release @ranges, so do it now. - */ - if (!dev_dax->nr_range) { - kfree(ranges); - ranges = NULL; - } - dev_dax->ranges = ranges; + if (!alloc) return -ENOMEM; + + ranges = krealloc(dev_dax->ranges, sizeof(*ranges) + * (dev_dax->nr_range + 1), GFP_KERNEL); + if (!ranges) { + rc = -ENOMEM; + goto err; } for (i = 0; i < dev_dax->nr_range; i++) @@ -808,11 +800,14 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start, dev_dbg(dev, "delete range[%d]: %pa:%pa\n", dev_dax->nr_range - 1, &alloc->start, &alloc->end); dev_dax->nr_range--; - __release_region(res, alloc->start, resource_size(alloc)); - return rc; + goto err; } return 0; + +err: + __release_region(res, alloc->start, resource_size(alloc)); + return rc; } static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size)
Swap the calling sequence of krealloc() and __request_region(), call the latter first. In this way, the value of dev_dax->nr_range does not need to be considered when __request_region() failed. Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> --- drivers/dax/bus.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-)