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Extend the device pager to support different memory attributes on different

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pages in an object.
- Add a new variant of d_mmap() currently called d_mmap2() which accepts
  an additional in/out parameter that is the memory attribute to use for
  the requested page.
- A driver either uses d_mmap() or d_mmap2() for all requests but not both.
  The current implementation uses a flag in the cdevsw (D_MMAP2) to indicate
  that the driver provides a d_mmap2() handler instead of d_mmap().  This
  is done to make the change ABI compatible with existing drivers and
  MFC'able to 7 and 8.

Submitted by:	alc
MFC after:	1 month
This commit is contained in:
John Baldwin 2009-08-28 14:06:55 +00:00
parent f105c8be8c
commit 2fa8c8d21e
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=196615
5 changed files with 41 additions and 16 deletions
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14
sys/kern/kern_conf.c
View File

@ -302,7 +302,7 @@ static struct cdevsw dead_cdevsw = {
#define no_read (d_read_t *)enodev
#define no_write (d_write_t *)enodev
#define no_ioctl (d_ioctl_t *)enodev
#define no_mmap (d_mmap_t *)enodev
#define no_mmap (d_mmap2_t *)enodev
#define no_kqfilter (d_kqfilter_t *)enodev
#define no_mmap_single (d_mmap_single_t *)enodev
@ -469,7 +469,8 @@ giant_kqfilter(struct cdev *dev, struct knote *kn)
}
static int
giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot)
giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot,
vm_memattr_t *memattr)
{
struct cdevsw *dsw;
int retval;
@ -478,7 +479,11 @@ giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot)
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_mmap(dev, offset, paddr, nprot);
if (dsw->d_gianttrick->d_flags & D_MMAP2)
retval = dsw->d_gianttrick->d_mmap2(dev, offset, paddr, nprot,
memattr);
else
retval = dsw->d_gianttrick->d_mmap(dev, offset, paddr, nprot);
mtx_unlock(&Giant);
dev_relthread(dev);
return (retval);
@ -614,6 +619,7 @@ prep_cdevsw(struct cdevsw *devsw)
if (devsw->d_gianttrick == NULL) {
memcpy(dsw2, devsw, sizeof *dsw2);
devsw->d_gianttrick = dsw2;
devsw->d_flags |= D_MMAP2;
dsw2 = NULL;
}
}
@ -634,7 +640,7 @@ prep_cdevsw(struct cdevsw *devsw)
FIXUP(d_write, no_write, giant_write);
FIXUP(d_ioctl, no_ioctl, giant_ioctl);
FIXUP(d_poll, no_poll, giant_poll);
FIXUP(d_mmap, no_mmap, giant_mmap);
FIXUP(d_mmap2, no_mmap, giant_mmap);
FIXUP(d_strategy, no_strategy, giant_strategy);
FIXUP(d_kqfilter, no_kqfilter, giant_kqfilter);
FIXUP(d_mmap_single, no_mmap_single, giant_mmap_single);

10
sys/sys/conf.h
View File

@ -137,6 +137,8 @@ typedef int d_poll_t(struct cdev *dev, int events, struct thread *td);
typedef int d_kqfilter_t(struct cdev *dev, struct knote *kn);
typedef int d_mmap_t(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr,
int nprot);
typedef int d_mmap2_t(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr,
int nprot, vm_memattr_t *memattr);
typedef int d_mmap_single_t(struct cdev *cdev, vm_ooffset_t *offset,
vm_size_t size, struct vm_object **object, int nprot);
typedef void d_purge_t(struct cdev *dev);
@ -170,6 +172,7 @@ typedef int dumper_t(
#define D_PSEUDO 0x00200000 /* make_dev() can return NULL */
#define D_NEEDGIANT 0x00400000 /* driver want Giant */
#define D_NEEDMINOR 0x00800000 /* driver uses clone_create() */
#define D_MMAP2 0x01000000 /* driver uses d_mmap2() */
/*
* Version numbers.
@ -198,7 +201,10 @@ struct cdevsw {
d_write_t *d_write;
d_ioctl_t *d_ioctl;
d_poll_t *d_poll;
d_mmap_t *d_mmap;
union {
d_mmap_t *old;
d_mmap2_t *new;
} __d_mmap;
d_strategy_t *d_strategy;
dumper_t *d_dump;
d_kqfilter_t *d_kqfilter;
@ -218,6 +224,8 @@ struct cdevsw {
SLIST_ENTRY(cdevsw) postfree_list;
} __d_giant;
};
#define d_mmap __d_mmap.old
#define d_mmap2 __d_mmap.new
#define d_gianttrick __d_giant.gianttrick
#define d_postfree_list __d_giant.postfree_list

1
sys/sys/types.h
View File

@ -299,6 +299,7 @@ typedef __uint32_t intrmask_t; /* Interrupt mask (spl, xxx_imask...) */
typedef __uintfptr_t uintfptr_t;
typedef __uint64_t uoff_t;
typedef char vm_memattr_t; /* memory attribute codes */
typedef struct vm_page *vm_page_t;
#define offsetof(type, field) __offsetof(type, field)

20
sys/vm/device_pager.c
View File

@ -93,6 +93,17 @@ dev_pager_init()
UMA_ZONE_NOFREE|UMA_ZONE_VM);
}
static __inline int
dev_mmap(struct cdevsw *csw, struct cdev *dev, vm_offset_t offset,
vm_paddr_t *paddr, int nprot, vm_memattr_t *memattr)
{
if (csw->d_flags & D_MMAP2)
return (csw->d_mmap2(dev, offset, paddr, nprot, memattr));
else
return (csw->d_mmap(dev, offset, paddr, nprot));
}
/*
* MPSAFE
*/
@ -106,6 +117,7 @@ dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
unsigned int npages;
vm_paddr_t paddr;
vm_offset_t off;
vm_memattr_t dummy;
struct cdevsw *csw;
/*
@ -133,7 +145,7 @@ dev_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
*/
npages = OFF_TO_IDX(size);
for (off = foff; npages--; off += PAGE_SIZE)
if ((*csw->d_mmap)(dev, off, &paddr, (int)prot) != 0) {
if (dev_mmap(csw, dev, off, &paddr, (int)prot, &dummy) != 0) {
dev_relthread(dev);
return (NULL);
}
@ -214,7 +226,6 @@ dev_pager_getpages(object, m, count, reqpage)
vm_memattr_t memattr;
struct cdev *dev;
int i, ret;
int prot;
struct cdevsw *csw;
struct thread *td;
struct file *fpop;
@ -228,12 +239,11 @@ dev_pager_getpages(object, m, count, reqpage)
csw = dev_refthread(dev);
if (csw == NULL)
panic("dev_pager_getpage: no cdevsw");
prot = PROT_READ; /* XXX should pass in? */
td = curthread;
fpop = td->td_fpop;
td->td_fpop = NULL;
ret = (*csw->d_mmap)(dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr, prot);
ret = dev_mmap(csw, dev, (vm_offset_t)offset << PAGE_SHIFT, &paddr,
PROT_READ, &memattr);
KASSERT(ret == 0, ("dev_pager_getpage: map function returns error"));
td->td_fpop = fpop;
dev_relthread(dev);

12
sys/vm/vm.h
View File

@ -63,12 +63,6 @@
#include <machine/vm.h>
/*
* The exact set of memory attributes is machine dependent. However, every
* machine is required to define VM_MEMATTR_DEFAULT.
*/
typedef char vm_memattr_t; /* memory attribute codes */
typedef char vm_inherit_t; /* inheritance codes */
#define VM_INHERIT_SHARE ((vm_inherit_t) 0)
@ -114,6 +108,12 @@ typedef struct vm_object *vm_object_t;
*/
typedef int boolean_t;
/*
* The exact set of memory attributes is machine dependent. However, every
* machine is required to define VM_MEMATTR_DEFAULT.
*/
typedef char vm_memattr_t; /* memory attribute codes */
/*
* This is defined in <sys/types.h> for the kernel so that vnode_if.h
* doesn't have to include <vm/vm.h>.