On Mon, Dec 18, 2017 at 09:48:37AM +0100, Zoltan Boszormenyi wrote: > From: Böszörményi Zoltán <zboszor@xxxxx> > > Add a new IORESOURCE_ALLOCATED flag that is automatically used > when alloc_resource() is used internally in kernel/resource.c > and free_resource() now takes this flag into account. > > The core of __request_region() was factored out into a new function > called __request_declared_region() that needs struct resource * > instead of the (start, n, name) triplet. > > These changes allow using statically declared struct resource > data coupled with the pre-existing DEFINE_RES_IO_NAMED() static > initializer macro. The new macro exploiting > __request_declared_region() is request_declared_muxed_region() > > v2: > > Fixed checkpatch.pl warnings and errors and extended the macro > API with request_declared_region() and release_declared_region() > > Reversed the order of __request_declared_region and __request_region > > Added high level description of the muxed and declared variants > of the macros. > > v3: > > Rebased for 4.15-rc4 > > Signed-off-by: Zoltán Böszörményi <zboszor@xxxxx> > --- > include/linux/ioport.h | 14 ++++++++++++++ > kernel/resource.c | 40 +++++++++++++++++++++++++++++++++++++--- > 2 files changed, 51 insertions(+), 3 deletions(-) > > diff --git a/include/linux/ioport.h b/include/linux/ioport.h > index 93b4183cf53d..d198d6a58574 100644 > --- a/include/linux/ioport.h > +++ b/include/linux/ioport.h > @@ -53,6 +53,7 @@ struct resource { > #define IORESOURCE_MEM_64 0x00100000 > #define IORESOURCE_WINDOW 0x00200000 /* forwarded by bridge */ > #define IORESOURCE_MUXED 0x00400000 /* Resource is software muxed */ > +#define IORESOURCE_ALLOCATED 0x00800000 /* Resource was allocated */ > > #define IORESOURCE_EXT_TYPE_BITS 0x01000000 /* Resource extended types */ > #define IORESOURCE_SYSRAM 0x01000000 /* System RAM (modifier) */ > @@ -218,7 +219,14 @@ static inline bool resource_contains(struct resource *r1, struct resource *r2) > > /* Convenience shorthand with allocation */ > #define request_region(start,n,name) __request_region(&ioport_resource, (start), (n), (name), 0) > +#define request_declared_region(res) __request_region( \ > + &ioport_resource, \ > + (res), 0) > #define request_muxed_region(start,n,name) __request_region(&ioport_resource, (start), (n), (name), IORESOURCE_MUXED) > +#define request_declared_muxed_region(res) __request_declared_region( \ > + &ioport_resource, \ > + (res), \ > + IORESOURCE_MUXED) > #define __request_mem_region(start,n,name, excl) __request_region(&iomem_resource, (start), (n), (name), excl) > #define request_mem_region(start,n,name) __request_region(&iomem_resource, (start), (n), (name), 0) > #define request_mem_region_exclusive(start,n,name) \ > @@ -230,8 +238,14 @@ extern struct resource * __request_region(struct resource *, > resource_size_t n, > const char *name, int flags); > > +extern struct resource *__request_declared_region(struct resource *parent, > + struct resource *res, int flags); > + > /* Compatibility cruft */ > #define release_region(start,n) __release_region(&ioport_resource, (start), (n)) > +#define release_declared_region(res) __release_region(&ioport_resource, \ > + (res)->start, \ > + (res)->end - (res)->start + 1) > #define release_mem_region(start,n) __release_region(&iomem_resource, (start), (n)) > > extern void __release_region(struct resource *, resource_size_t, > diff --git a/kernel/resource.c b/kernel/resource.c > index 54ba6de3757c..05db9c4e3992 100644 > --- a/kernel/resource.c > +++ b/kernel/resource.c > @@ -184,6 +184,9 @@ static void free_resource(struct resource *res) > if (!res) > return; > > + if (!(res->flags & IORESOURCE_ALLOCATED)) > + return; > + > if (!PageSlab(virt_to_head_page(res))) { > spin_lock(&bootmem_resource_lock); > res->sibling = bootmem_resource_free; > @@ -210,6 +213,8 @@ static struct resource *alloc_resource(gfp_t flags) > else > res = kzalloc(sizeof(struct resource), flags); > > + res->flags = IORESOURCE_ALLOCATED; > + kzalloc() can fail, thus res can be NULL. > return res; > } > > @@ -1128,8 +1133,19 @@ resource_size_t resource_alignment(struct resource *res) > * the IO flag meanings (busy etc). > * > * request_region creates a new busy region. > + * The resource descriptor is allocated by this function. > + * > + * request_declared_region creates a new busy region > + * described in an existing resource descriptor. > + * > + * request_muxed_region creates a new shared busy region. > + * The resource descriptor is allocated by this function. > + * > + * request_declared_muxed_region creates a new shared busy region > + * described in an existing resource descriptor. > * > * release_region releases a matching busy region. > + * The region is only freed if it was allocated. > */ > > static DECLARE_WAIT_QUEUE_HEAD(muxed_resource_wait); > @@ -1146,7 +1162,6 @@ struct resource * __request_region(struct resource *parent, > resource_size_t start, resource_size_t n, > const char *name, int flags) > { > - DECLARE_WAITQUEUE(wait, current); > struct resource *res = alloc_resource(GFP_KERNEL); > > if (!res) > @@ -1156,6 +1171,26 @@ struct resource * __request_region(struct resource *parent, > res->start = start; > res->end = start + n - 1; > > + if (!__request_declared_region(parent, res, flags)) { > + free_resource(res); > + res = NULL; > + } > + > + return res; > +} > +EXPORT_SYMBOL(__request_region); > + > +/** > + * __request_declared_region - create a new busy resource region > + * @parent: parent resource descriptor > + * @res: child resource descriptor > + * @flags: IO resource flags > + */ > +struct resource *__request_declared_region(struct resource *parent, > + struct resource *res, int flags) > +{ > + DECLARE_WAITQUEUE(wait, current); > + > write_lock(&resource_lock); > > for (;;) { > @@ -1184,14 +1219,13 @@ struct resource * __request_region(struct resource *parent, > continue; > } > /* Uhhuh, that didn't work out.. */ > - free_resource(res); > res = NULL; > break; > } > write_unlock(&resource_lock); > return res; > } > -EXPORT_SYMBOL(__request_region); > +EXPORT_SYMBOL(__request_declared_region); > > /** > * __release_region - release a previously reserved resource region > -- > 2.13.6 >