ddi_umem_unlock(9f) [sunos man page]
ddi_umem_lock(9F) Kernel Functions for Drivers ddi_umem_lock(9F) NAME
ddi_umem_lock, ddi_umem_unlock - lock and unlock memory pages SYNOPSIS
#include <sys/ddi.h> #include <sys/sunddi.h> int ddi_umem_lock(caddr_t addr, size_t len, int flags, ddi_umem_cookie_t *cookiep); void ddi_umem_unlock(ddi_umem_cookie_t cookie); INTERFACE LEVEL
Solaris DDI specific (Solaris DDI) PARAMETERS
ddi_umem_lock addr Virtual address of memory object len Length of memory object in bytes flags Valid flags include: DDI_UMEMLOCK_READ Memory pages are locked to be read from. (Disk write or a network send.) DDI_UMEMLOCK_WRITE Memory pages are locked to be written to. (Disk read or a network receive.) cookiep Pointer to a kernel memory cookie. ddi_umem_unlock cookie Kernel memory cookie allocated by ddi_umem_lock(). DESCRIPTION
The ddi_umem_lock(9F) function locks down the physical pages (including I/O pages) that correspond to the current process' virtual address range [addr, addr + size) and fills in a cookie representing the locked pages. This cookie can be used to create a buf(9S) structure that can be used to perform I/O (see ddi_umem_iosetup(9F) and ddi_dma_buf_bind_handle(9F)), or it can be used with devmap_umem_setup(9F) to export the memory to an application. The virtual address and length specified must be at a page boundary and the mapping performed in terms of the system page size. See page- size(1). The flags argument indicates the intended use of the locked memory. Set flags to DDI_UMEMLOCK_READ if the memory pages will be read (for example, in a disk write or a network send.) Set flags to DDI_UMEMLOCK_WRITE if the memory pages will be written (for example, in a disk read or a network receive). You must choose one (and only one) of these values. To unlock the locked pages, the drivers call ddi_umem_unlock(9F) with the cookie obtained from ddi_umem_lock(9F). The process is not allowed to exec(2) or fork(2) while its physical pages are locked down by the device driver. The device driver must ensure that the physical pages have been unlocked after the application has called close(2). RETURN VALUES
On success, a 0 is returned. Otherwise, one of the following errno values is returned. EFAULT User process has no mapping at that address range or does not support locking EACCES User process does not have the required permission. ENOMEM The system does not have sufficient resources to lock memory. EAGAIN Could not allocate system resources required to lock the pages. The ddi_umem_lock() could succeed at a later time. EINVAL Requested memory is not aligned on a system page boundary. CONTEXT
The ddi_umem_lock() function can only be called from user context; ddi_umem_unlock() from user, kernel, and interrupt contexts. SEE ALSO
ddi_umem_iosetup(9F), ddi_dma_buf_bind_handle(9F), devmap_umem_setup(9F), ddi_umem_alloc(9F) NOTES
The ddi_umem_lock(9F) function consumes physical memory. The driver is responsible for a speedy unlock to free up the resources. ddi_umem_unlock() can defer unlocking of the pages to a later time depending on the implementation. SunOS 5.10 4 Feb 2003 ddi_umem_lock(9F)
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ddi_umem_lock(9F) Kernel Functions for Drivers ddi_umem_lock(9F) NAME
ddi_umem_lock, ddi_umem_unlock - lock and unlock memory pages SYNOPSIS
#include <sys/ddi.h> #include <sys/sunddi.h> int ddi_umem_lock(caddr_t addr, size_t len, int flags, ddi_umem_cookie_t *cookiep); void ddi_umem_unlock(ddi_umem_cookie_t cookie); INTERFACE LEVEL
Solaris DDI specific (Solaris DDI) PARAMETERS
ddi_umem_lock addr Virtual address of memory object len Length of memory object in bytes flags Valid flags include: DDI_UMEMLOCK_READ Memory pages are locked to be read from. (Disk write or a network send.) DDI_UMEMLOCK_WRITE Memory pages are locked to be written to. (Disk read or a network receive.) cookiep Pointer to a kernel memory cookie. ddi_umem_unlock cookie Kernel memory cookie allocated by ddi_umem_lock(). DESCRIPTION
The ddi_umem_lock(9F) function locks down the physical pages (including I/O pages) that correspond to the current process' virtual address range [addr, addr + size) and fills in a cookie representing the locked pages. This cookie can be used to create a buf(9S) structure that can be used to perform I/O (see ddi_umem_iosetup(9F) and ddi_dma_buf_bind_handle(9F)), or it can be used with devmap_umem_setup(9F) to export the memory to an application. The virtual address and length specified must be at a page boundary and the mapping performed in terms of the system page size. See page- size(1). The flags argument indicates the intended use of the locked memory. Set flags to DDI_UMEMLOCK_READ if the memory pages will be read (for example, in a disk write or a network send.) Set flags to DDI_UMEMLOCK_WRITE if the memory pages will be written (for example, in a disk read or a network receive). You must choose one (and only one) of these values. To unlock the locked pages, the drivers call ddi_umem_unlock(9F) with the cookie obtained from ddi_umem_lock(9F). The process is not allowed to exec(2) or fork(2) while its physical pages are locked down by the device driver. The device driver must ensure that the physical pages have been unlocked after the application has called close(2). RETURN VALUES
On success, a 0 is returned. Otherwise, one of the following errno values is returned. EFAULT User process has no mapping at that address range or does not support locking EACCES User process does not have the required permission. ENOMEM The system does not have sufficient resources to lock memory. EAGAIN Could not allocate system resources required to lock the pages. The ddi_umem_lock() could succeed at a later time. EINVAL Requested memory is not aligned on a system page boundary. CONTEXT
The ddi_umem_lock() function can only be called from user context; ddi_umem_unlock() from user, kernel, and interrupt contexts. SEE ALSO
ddi_umem_iosetup(9F), ddi_dma_buf_bind_handle(9F), devmap_umem_setup(9F), ddi_umem_alloc(9F) NOTES
The ddi_umem_lock(9F) function consumes physical memory. The driver is responsible for a speedy unlock to free up the resources. ddi_umem_unlock() can defer unlocking of the pages to a later time depending on the implementation. SunOS 5.10 4 Feb 2003 ddi_umem_lock(9F)