| Message ID | 20250107141015.3367194-7-rrichter@amd.com |
|---|---|
| State | New |
| Headers | show |
| Series | cxl: Add address translation support and enable AMD Zen5 platforms | expand |
On Tue, Jan 07, 2025 at 03:09:52PM +0100, Robert Richter wrote: > In function cxl_add_to_region() there is code to determine the root > decoder associated to an endpoint decoder. Factor out that code for > later reuse. This also simplifies the function cxl_add_to_region() as > the change reduces its size and the number of used variables. > > The reference of cxlrd_dev can be freed earlier. Since the root > decoder exists as long as the root port exists and the endpoint > already holds a reference to the root port, this additional reference > is not needed. Though it looks obvious to use __free() for the > reference of cxlrd_dev here too, this is done in a later rework. So > just move the code. > > Signed-off-by: Robert Richter <rrichter@amd.com> > --- > drivers/cxl/core/region.c | 55 ++++++++++++++++++++++++++------------- > 1 file changed, 37 insertions(+), 18 deletions(-) > Reviewed-by: Gregory Price <gourry@gourry.net>
On Tue, 7 Jan 2025 15:09:52 +0100 Robert Richter <rrichter@amd.com> wrote: > In function cxl_add_to_region() there is code to determine the root > decoder associated to an endpoint decoder. Factor out that code for > later reuse. This also simplifies the function cxl_add_to_region() as > the change reduces its size and the number of used variables. > > The reference of cxlrd_dev can be freed earlier. Since the root > decoder exists as long as the root port exists and the endpoint > already holds a reference to the root port, this additional reference > is not needed. Though it looks obvious to use __free() for the > reference of cxlrd_dev here too, this is done in a later rework. So > just move the code. > > Signed-off-by: Robert Richter <rrichter@amd.com> One trivial comment inline. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- > drivers/cxl/core/region.c | 55 ++++++++++++++++++++++++++------------- > 1 file changed, 37 insertions(+), 18 deletions(-) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 752440a5c162..448408918def 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -3202,6 +3202,38 @@ static int match_root_decoder_by_range(struct device *dev, void *data) > return range_contains(r1, r2); > } > > +static struct cxl_root_decoder * > +cxl_find_root_decoder(struct cxl_endpoint_decoder *cxled) > +{ > + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); > + struct cxl_port *port = cxled_to_port(cxled); > + struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port); > + struct range *hpa = &cxled->cxld.hpa_range; > + struct cxl_decoder *cxld = &cxled->cxld; Flip this and the line above and you can have struct range *hpa = cxld->hpa_range; which is both shorter and matches original code save a few moments of thinking. > + struct device *cxlrd_dev; > + > + cxlrd_dev = device_find_child(&cxl_root->port.dev, hpa, > + match_root_decoder_by_range); > + if (!cxlrd_dev) { > + dev_err(cxlmd->dev.parent, > + "%s:%s no CXL window for range %#llx:%#llx\n", > + dev_name(&cxlmd->dev), dev_name(&cxld->dev), > + cxld->hpa_range.start, cxld->hpa_range.end); > + return NULL; > + } > + > + /* > + * device_find_child() created a reference to the root > + * decoder. Since the root decoder exists as long as the root > + * port exists and the endpoint already holds a reference to > + * the root port, this additional reference is not needed. > + * Free it here. > + */ > + put_device(cxlrd_dev); > + > + return to_cxl_root_decoder(cxlrd_dev); > +} > + > static int match_region_by_range(struct device *dev, void *data) > { > struct cxl_region_params *p; > @@ -3309,29 +3341,17 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, > > int cxl_add_to_region(struct cxl_endpoint_decoder *cxled) > { > - struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); > - struct cxl_port *port = cxled_to_port(cxled); > - struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port); > struct range *hpa = &cxled->cxld.hpa_range; > - struct cxl_decoder *cxld = &cxled->cxld; > - struct device *cxlrd_dev, *region_dev; > + struct device *region_dev; > struct cxl_root_decoder *cxlrd; > struct cxl_region_params *p; > struct cxl_region *cxlr; > bool attach = false; > int rc; > > - cxlrd_dev = device_find_child(&cxl_root->port.dev, &cxld->hpa_range, > - match_root_decoder_by_range); > - if (!cxlrd_dev) { > - dev_err(cxlmd->dev.parent, > - "%s:%s no CXL window for range %#llx:%#llx\n", > - dev_name(&cxlmd->dev), dev_name(&cxld->dev), > - cxld->hpa_range.start, cxld->hpa_range.end); > + cxlrd = cxl_find_root_decoder(cxled); > + if (!cxlrd) > return -ENXIO; > - } > - > - cxlrd = to_cxl_root_decoder(cxlrd_dev); > > /* > * Ensure that if multiple threads race to construct_region() for @hpa > @@ -3349,7 +3369,7 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled) > > rc = PTR_ERR_OR_ZERO(cxlr); > if (rc) > - goto out; > + return rc; > > attach_target(cxlr, cxled, -1, TASK_UNINTERRUPTIBLE); > > @@ -3370,8 +3390,7 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled) > } > > put_device(region_dev); > -out: > - put_device(cxlrd_dev); > + > return rc; > } > EXPORT_SYMBOL_NS_GPL(cxl_add_to_region, "CXL");
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 752440a5c162..448408918def 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -3202,6 +3202,38 @@ static int match_root_decoder_by_range(struct device *dev, void *data) return range_contains(r1, r2); } +static struct cxl_root_decoder * +cxl_find_root_decoder(struct cxl_endpoint_decoder *cxled) +{ + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); + struct cxl_port *port = cxled_to_port(cxled); + struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port); + struct range *hpa = &cxled->cxld.hpa_range; + struct cxl_decoder *cxld = &cxled->cxld; + struct device *cxlrd_dev; + + cxlrd_dev = device_find_child(&cxl_root->port.dev, hpa, + match_root_decoder_by_range); + if (!cxlrd_dev) { + dev_err(cxlmd->dev.parent, + "%s:%s no CXL window for range %#llx:%#llx\n", + dev_name(&cxlmd->dev), dev_name(&cxld->dev), + cxld->hpa_range.start, cxld->hpa_range.end); + return NULL; + } + + /* + * device_find_child() created a reference to the root + * decoder. Since the root decoder exists as long as the root + * port exists and the endpoint already holds a reference to + * the root port, this additional reference is not needed. + * Free it here. + */ + put_device(cxlrd_dev); + + return to_cxl_root_decoder(cxlrd_dev); +} + static int match_region_by_range(struct device *dev, void *data) { struct cxl_region_params *p; @@ -3309,29 +3341,17 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, int cxl_add_to_region(struct cxl_endpoint_decoder *cxled) { - struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); - struct cxl_port *port = cxled_to_port(cxled); - struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port); struct range *hpa = &cxled->cxld.hpa_range; - struct cxl_decoder *cxld = &cxled->cxld; - struct device *cxlrd_dev, *region_dev; + struct device *region_dev; struct cxl_root_decoder *cxlrd; struct cxl_region_params *p; struct cxl_region *cxlr; bool attach = false; int rc; - cxlrd_dev = device_find_child(&cxl_root->port.dev, &cxld->hpa_range, - match_root_decoder_by_range); - if (!cxlrd_dev) { - dev_err(cxlmd->dev.parent, - "%s:%s no CXL window for range %#llx:%#llx\n", - dev_name(&cxlmd->dev), dev_name(&cxld->dev), - cxld->hpa_range.start, cxld->hpa_range.end); + cxlrd = cxl_find_root_decoder(cxled); + if (!cxlrd) return -ENXIO; - } - - cxlrd = to_cxl_root_decoder(cxlrd_dev); /* * Ensure that if multiple threads race to construct_region() for @hpa @@ -3349,7 +3369,7 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled) rc = PTR_ERR_OR_ZERO(cxlr); if (rc) - goto out; + return rc; attach_target(cxlr, cxled, -1, TASK_UNINTERRUPTIBLE); @@ -3370,8 +3390,7 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled) } put_device(region_dev); -out: - put_device(cxlrd_dev); + return rc; } EXPORT_SYMBOL_NS_GPL(cxl_add_to_region, "CXL");
In function cxl_add_to_region() there is code to determine the root decoder associated to an endpoint decoder. Factor out that code for later reuse. This also simplifies the function cxl_add_to_region() as the change reduces its size and the number of used variables. The reference of cxlrd_dev can be freed earlier. Since the root decoder exists as long as the root port exists and the endpoint already holds a reference to the root port, this additional reference is not needed. Though it looks obvious to use __free() for the reference of cxlrd_dev here too, this is done in a later rework. So just move the code. Signed-off-by: Robert Richter <rrichter@amd.com> --- drivers/cxl/core/region.c | 55 ++++++++++++++++++++++++++------------- 1 file changed, 37 insertions(+), 18 deletions(-)